List of ''The Patty Duke Show'' episodes

Patty Lane's European cousin, Cathy Lane (Patty Duke in a dual role), comes to Brooklyn Heights to live with the Lane family.

Patty falls for her substitute French teacher.

Patty inadvertently alters a computerized IQ test. As a result, she is mistakenly categorized as a genius.

Martin mistakenly believes that the family is trying to hide the fact that Patty and Richard are going to sneak off and get married, but Cathy's hiccups give them away.

Crotchety Aunt Pauline (guest star Ilka Chase) comes to the Lane household for her annual visit. Things seem to be going as good as can be expected until Aunt Pauline has a confrontation with Cathy over the way her father has been raising her.

A girl invites Ross to his first party, but Ross is hesitant to go. Patty and Cathy get involved, but will that change Ross' mind?

Patty and Cathy have a slumber party at their house for some of their girlfriends. Richard, Henry, Tom and another boy show up at the door, before the party starts. Unbeknownst to Patty and Cathy, Ross tapes the girls' conversations during the party and uses it for blackmail against them. The two cousins end up doing his chores, to keep Ross from playing the tape to others and wait on him constantly. Patty and Cathy eventually turn the table on Ross and everything works out fine in the end for the entire Lane family.

Cathy helps Brooklyn Heights high school's best basketball player prepare for a class test. If he fails, he will be ineligible for the big game.

Patty and Cathy unknowingly nominate each other for President of the Girls League. What begins as a friendly rivalry turns into a battle of wills and some dirty campaigning.

Through no fault of their own, Cathy accidentally gets the flu shot that was meant for Patty. Cathy's reaction to the shot causes her to miss the dance party later that night, so Patty decides to pull a double shift so Cathy won't lose her boyfriend.

After feeling like a wallflower at one of Patty's parties, Cathy asks a newspaper columnist how she can be more popular. Cathy tries hard, but the results are not what she expects.

In order to win Richard back, Patty, on the advice of her mother, decides to write a poem. After having no luck writing one on her own, Patty finds a poem in a book and gives that one to Richard. Everyone thinks that Patty wrote the poem and it's not a problem until Cathy puts the words to music and Richard decides to enter the song into a TV contest.

Martin is forced by his boss, J.R. Castle, to fire his twin brother, Kenneth, at Christmastime.

Now that Uncle Kenneth has made it home and been fired from his job, Patty and Cathy scheme to get him rehired.

After a few horoscope predictions come true, Patty sees this as an opportunity to make a few quick bucks to help buy a birthday present for her mom. As business booms, she enlists Cathy to "double" their profits.

When a dress made by Cathy becomes a hit at school, Patty decides to market the dresses to a wider audience. Soon, however, the difficulties of owning a growing business become all too real.

Martin's newspaper reassigns him to the Paris bureau for a year. At first, the entire family is enthusiastic about the trip, but the enthusiasm begins to wane when each family member realizes what they are leaving behind.

Patty accepts Richard's ring and they both decide to go steady. Both of their families think they are too young to steady so they conspire to change Patty and Richard's minds.

Patty takes a test in a magazine to see how good of a teenager she is. Her self-confidence plummets when she fails the test, so she decides to take a modeling class to try to regain her confidence.

Patty becomes editor of the school newspaper. Seeking to get a quick increase in readership, she avoids modeling the paper after her father's and instead goes the tabloid route.

Patty finds a pen pal through the newspaper and soon decides that her new pal is superior to Richard.

Shortly after Cathy receives a present for doing well on a test, Patty begins uncontrollable sneezing whenever she gets near Cathy. The family believes the sneezing is a psychosomatic result of Patty's jealousy of Cathy, while Cathy thinks it's because Patty hates her.

Patty gets an expensive dress for a school dance. But before Patty can pay for it, Cathy borrows the dress, with disastrous results.

Richard decides to drop out of high school and Patty, in turn, decides to drop him.

After Patty is put in charge of the school prom she poses as Cathy in order to get Cathy's old school friend Bertram "Binky" Bristol, who has become a pop star, to perform at the dance.

Cathy is chosen to be student principal for the week. As part of her duties, she is assigned to teach a class. In that class, Patty begins to disrupt things and Cathy has no choice but to reprimand her.

Patty and Cathy reminisce about the time when Cathy first came to live with the Lane family.

Note: This episode features parts of the unaired pilot, with William Schallert and Paul O'Keefe in their respective roles of Martin and Ross Lane; this is also John McGiver's final appearance in the series, guest-starring as J.R. Castle, Martin and Kenneth's boss at The New York Daily Chronicle.

A new boy in town competes with Richard for Patty's affections. Patty's mom and dad take sides on which boy to give advice to.

Patty writes an advice to the loverlorn column for the school newspaper, but most of her readers are not happy with her advice, especially Cathy.

Patty and Cathy campaign for a family friend's run at a congressional seat. They are less enthusiastic when they disagree with his platform.

Patty gets invited to a college prom but her parents won't let her attend. Taking Cathy's advice, she decides to use a little psychology to get her way.

Patty feels the need for something more in life and decides to sign up for the Peace Corps.

Cathy falls for the new boy at school, despite all of the advice given to her by the rest of the family.

After some stocks that her father bought for her increases in value, Patty decides to sell stock in a new company: Patty Lane, Inc.

Patty battles her archrival Sue Ellen for the new boy at school.

Patty believes that she has witnessed a crime and now she thinks that the mob is going rub her out.

Patty believes that her parents are trying to marry her off to a man she doesn't even know. Her only recourse is to act as unappealing as possible in order to discourage the marriage.

Patty and Cathy's cousin Betsy (Patty Duke in a triple role) comes to stay with the Lanes on her vacation from boarding school. After a while, Patty begins to believe that Betsy is trying to come between her and Cathy.

Cathy is chosen to show Sal Mineo around his old Brooklyn Heights High School, but Patty thinks the honor should go to her. Cathy relents and Patty gets a chance to act with Sal Mineo in a school play.

Patty decides to have a raffle to benefit the church bazaar. The prize? A date with Richard. But can Patty stand it if one of her rivals wins the prize?

Martin thinks that he is being phased out as managing editor of the Chronicle, just as Patty falls for his presumed replacement.

When Cathy is chosen to host a classical music program on a Brooklyn Heights radio station, Patty sees this as an opportunity to promote a new singing duo she has discovered.

After Patty's success at getting a star to appear at last year's school prom, she gets selected to do the same for this year's prom.

Patty falls head-over-heels for her new science teacher and her studying genetics of 19th century scientist Gregor Mendel only serves to convince her that their genes are a perfect match and being his wife is her destiny.

After Patty breaks a date with Richard, Cathy and Richard begin dating. This leads to some tension between the cousins, all the while Richard lets his newfound desirability go to his head.

Martin begins to feel he is losing touch with his daughter Patty and would like to spend more time with her. When Patty agrees, Martin begins to realize that he may be getting more than he bargained for.

Even though her father forbids it, Patty wants to be a folk singer at the local coffee house and brings Richard along as her manager.

Patty, because of her lack of cooking skills, fears that she is losing Richard to a rival, so Patty enlists Cathy to cook for her in order to get Richard back, but the plan backfires when Cathy is called away before she can prepare the meal.

Patty's father bets her that she can't remain silent for 72 hours. Patty takes that bet but later regrets it when it interferes with her spot on the debate team.

Frankie Avalon's car breaks down in front of the Lane house so he asks if he can use their telephone. Once Patty realizes who it is, she is determined to spend some time with Mr. Avalon.

Patty needs to have her tonsils removed and her surgeon just so happens to look like Troy Donahue, much to Patty's delight. What she doesn't know is that her surgeon really is Troy Donahue. Overhearing him brag about his new boat, she thinks he is describing her.

Patty's rival, Monica Robinson, throws a party, but she doesn't invite Cathy. Patty gets Cathy invited, but at the expense of losing Richard on a date to Monica, so Patty decides to skip the party, that is, until she learns that a musical group needs a lead singer and there is a possibility of a record deal at the party.

Patty paints a painting at school, but everyone is afraid give their honest opinion about it. Will they put their money where their mouth is when the painting goes up for auction?

Patty takes a shy student under her wing in order to teach her how to be more popular, but Patty faces a dilemma when she proves to be too good of a teacher.

An Interpol spy, who is also a friend of Cathy's father, comes from London, England to visit the Lane family, but Patty thinks he is there on official business.

Patty gets a job as a nurses assistant at the hospital. Unfortunately for her dad, he ends up at the hospital, too, after slipping on Ross' skateboard.

The family camps out in the backyard as a test run for their summer vacation.

With her history grades faltering at school, Patty befriends a new student, who just happens to be good at history.

In order to make a few bucks, Patty offers to take care of a woman's dog, a dog that just happens to have a list of peculiar needs.

As part of a school project, Patty writes a letter to a Soviet politician. While she is stunned to get a reply, she is even more surprised when the State Department gets involved.

After Patty receives a dress from Cathy, who is on vacation in Paris with her dad, she decides to throw her first adult party, but things get complicated when Uncle Jed arrives; to make matters worse, a power outage hits Brooklyn Heights right before the party.

To teach Patty a lesson, Cathy encourages the family to trick Patty into thinking she has psychic abilities. After Patty starts giving readings to her classmates, an actual psychic takes interest in her abilities.

After friends of Patty and Richard's get married, they decide to do the same. At first, this idea sounds like a dream, but later turns into a nightmare.

In order to secure a date from a neighborhood boy, Patty convinces Ross to do some chores for him.

Ross' only chance to get into a basketball club is for Patty to date the club's president. Unfortunately for Patty, she can't stand the guy.