In 1989, Klugman's throat cancer (with which he was first diagnosed in 1974) returned.
His illness sidelined his career for the next four years.
He returned to acting in a 1993 Broadway revival of Three Men on a Horse.
That same year, he reunited with Tony Randall in the television film The Odd Couple: Together Again.
The next year, Klugman co-starred in the television film Parallel Lives.

In 1993, he appeared on a special "celebrity versus regulars" version of the British quiz show Going for Gold, emerging as the series winner.

In 1996, he co-starred in The Twilight of the Golds and the comedy film Dear God.
He resumed his television career with guest spots on Diagnosis: Murder.
He also starred in The Outer Limits episode "Glitch", and appeared in an episode of the TV series Crossing Jordan.
In 1997, Klugman starred in the Broadway, then in 2007, Off-Broadway revival of The Sunshine Boys.

In 2005, Klugman co-starred in the comedy film When Do We Eat?.
That same year, he published Tony and Me: A Story of Friendship, a book about his long friendship with his The Odd Couple co-star Tony Randall.
Klugman gave the eulogy at Randall's memorial service in 2004.
Klugman, who liked the same New York Mets whose cap he wore as Oscar Madison, started an MLB.com PRO Blog called Klugman's Korner to talk about baseball and Randall.

In 2008, he sued NBC Television concerning missing profits from his show Quincy M.E. The lawsuit was filed in California Superior Court, with Klugman requesting NBC to show him the original contract.
Klugman stated that his production company, Sweater Productions, should have received 25% of the show's net profits.
NBC Universal and Klugman settled the lawsuit on undisclosed terms in August 2010.

His last on-screen role was in the 2010 horror film Camera Obscura.
Klugman was originally supposed to play Juror #9 in a stage production of Twelve Angry Men at the George Street Playhouse, set to open on March 13, 2012.
However, he had to withdraw from the production due to illness.
In 1989, Klugman's throat cancer (with which he was first diagnosed in 1974) returned. His illness sidelined his career for the next four years. He returned to acting in a 1993 Broadway revival of Three Men on a Horse. That same year, he reunited with Tony Randall in the television film The Odd Couple: Together Again. The next year, Klugman co-starred in the television film Parallel Lives.
In 1993, he appeared on a special "celebrity versus regulars" version of the British quiz show Going for Gold, emerging as the series winner.
In 1996, he co-starred in The Twilight of the Golds and the comedy film Dear God. He resumed his television career with guest spots on Diagnosis: Murder. He also starred in The Outer Limits episode "Glitch", and appeared in an episode of the TV series Crossing Jordan. In 1997, Klugman starred in the Broadway, then in 2007, Off-Broadway revival of The Sunshine Boys.
In 2005, Klugman co-starred in the comedy film When Do We Eat?. That same year, he published Tony and Me: A Story of Friendship, a book about his long friendship with his The Odd Couple co-star Tony Randall. Klugman gave the eulogy at Randall's memorial service in 2004. Klugman, who liked the same New York Mets whose cap he wore as Oscar Madison, started an MLB.com PRO Blog called Klugman's Korner to talk about baseball and Randall.
In 2008, he sued NBC Television concerning missing profits from his show Quincy M.E. The lawsuit was filed in California Superior Court, with Klugman requesting NBC to show him the original contract. Klugman stated that his production company, Sweater Productions, should have received 25% of the show's net profits. NBC Universal and Klugman settled the lawsuit on undisclosed terms in August 2010.
His last on-screen role was in the 2010 horror film Camera Obscura. Klugman was originally supposed to play Juror #9 in a stage production of Twelve Angry Men at the George Street Playhouse, set to open on March 13, 2012. However, he had to withdraw from the production due to illness.
Jack Klugman