USA's comedy series "Psych" is the network's longest-running original series. On the air since 2006, the show is fast approaching the 100 episode mark. Given the fact that USA has only operated under that name since 1979 and originally started out as a sports channel, it's not surprising that such a relatively young series would have the honor of being USA's longest-running original series.
But for other networks that have been around longer than USA, a paltry six seasons (with a seventh on the way) can't compare to some of the truly long-running series. Apart from long-running daytime soap operas like "As the World Turns," "General Hospital," and "Days of our Lives," here are the longest-running programs on some of America's major TV networks.
Fox: "The Simpsons""The Simpsons" has been on the air since December of 1989, and is the longest-running scripted series on Fox. It's also the longest-running American sitcom and the longest-running cartoon with over 500 episodes aired to date. In 2009, "The Simpsons" garnered another honor: It surpassed the famous Western series "Gunsmoke" for the title of longest-running, scripted American primetime series. And while fans love to carp about how the more recent seasons aren't as good as the show's early episodes, "The Simpsons" shows no signs of stopping. "America's Most Wanted," on the air on Fox since 1988, also deserves a mention.
NBC: "Saturday Night Live"To date, "Saturday Night Live" has aired 716 episodes. On the air since October of 1975, the show doesn't air a new episode every single Saturday night, but has been the inspiration for tons of movies and an untold number of comics. Also note worthy is "Law & Order," which has only been on the air since 1990, but has spawned almost 450 episodes and several spin-off series.
CBS: "Gunsmoke"As mentioned above, "Gunsmoke" was de-throned in 2009 of the title of longest-running scripted American primetime series. "Gunsmoke" told the story of cowboys and outlaws in Dodge City, and actually had its origins in a radio program. The TV version aired from September 10, 1955, to September 1, 1975. All told, 635 episodes aired, but with the current network passion for rebooting old shows like "Dallas," it may not be long before "Gunsmoke" also gets a modern-day continuation. Similarly long-running was "Lassie," which ran on CBS from 1954 to 1971, and was later picked for a TV series during the 1980s and 1990s.