When Law & Order: Special Victims Unit was renewed for a 20th season, the show joined elite company as one of the longest-running shows of all time.
SVU will be the longest-running drama series in TV history, tying with the Western Gunsmoke and the original Law & Order.
The new season of SVU will air on Thursdays on NBC at 10 p.m. ET, following two hours of sitcoms. Season 19, which wrapped up last month, aired on Wednesdays.
What makes SVU's success remarkable is that the show's popularity shows no signs of slowing. Although its average rating in the 18-49 demographic was down from season 18, the show gained in total viewers. According to TVSeriesFinale, the show averaged 5.9 million viewers, a 2.06 percent jump from the previous year.
"I don't see any reason why this show will end," showrunner Michael Chernuchin told TV Guide last week. "[We're going to continue] until Mariska [Hargitay] says, 'let's end it,' because we're dealing with things that are on the front page in the papers every day. Now, more than ever."
Scroll on for a look at the 10 longest-running primetime U.S. TV series of all time.
The Simpsons (Fox)
The Simpsons debuted on Fox on Dec. 17, 1989 and is now up to 29 seasons. Its 30th season will start this fall. The show is the longest-running sitcom, the longest-running animated show and the longest-running primetime American TV show overall.
Although the show's critical glory days are far behind it, The Simpsons has shown no signs of ending. Since the show started, 639 episodes have aired.prevnext
America's Funniest Home Videos (ABC)
In the age of YouTube, when we can instantly watch funny videos at any time, America's Funniest Home Videos seems like a relic. But the show has survived hosting changes and technological advances to become the second-longest running series in TV history. Like The Simpsons, it also debuted in 1989, but has run 28 seasons. The show, now hosted by Alfonso Ribeiro, will be back in the fall.prevnext
Gunsmoke was a beloved Western series, which aired on CBS from September 1955 to March 1975. The series started on the radio in 1952, with the radio show ending in 1961. James Arness and Mulburn Stone starred in all 20 seasons and 635 episodes.prevnext
Law & Order (NBC)
Dick Wolf's original Law & Order launched in September 1990 and finished in May 2010. Sadly, the show was cancelled without giving a proper send-off.
What made Law & Order's successful was the format. Although stars like S. Epatha Merkerson, Jerry Orbach and Sam Waterston created unforgettable characters, the show survived casting frequent casting changes. It lives on in syndication, where fans can watch any episode without needing to know a whole character's backstory. The cases were front and center.prevnext
Law & Order: SVU (NBC)
SVU is the only Law & Order spin-off still on the air. Like the original show, it continues to survive despite the casting changes. However, it would not be the same without Mariska Hargitay, who has been in every single season. Not even the original L&O had a castmember on as long as Hargitay. Ice-T joined in season two and has been on the series ever since.prevnext
Lassie ran an astonishing 17 seasons. The first 15 aired on CBS, but the last two were in syndication. The series ran 591 episodes, and was inspired by Eric Knight's 1938 novel Lassie Come-Home. The book also inspired MGM's movie franchise, which included seven films made between 1943 and 1951.prevnext
Family Guy (Fox)
Fox's next series on the list is Seth MacFarlane's Family Guy, another animated family sitcom. The show debuted in 1999 and was initially cancelled in 2003. But the show was saved thanks to DVD sales and the high ratings repeats got on Adult Swim. The show returned in 2005 and has been on Fox ever since. The show is up to 309 episodes.prevnext
NCIS debuted in 2003 and has the distinction of running longer than the show it spun out of. Mark Harmon's character debuted in JAG, which ran on NBC and CBS from 1995 to 2005, for 227 episodes in 10 seasons. NCIS is up to 354 episodes in 15 seasons, and is the most-watched drama on broadcast TV. The show's 15th season averaged 13 million viewers, reports TVSeriesFinale.
NCIS has inspired two of its own spin-offs, NCIS: Los Angeles and NCIS: New Orleans.prevnext
CSI: Crime Scene Investigation (CBS)
CSI was once an international juggernaut, and ran from 15 seasons with 337 episodes. The show ran from October 2000 to February 2015. In September 2015, the two-hour movie "Immortality" aired, giving fans a welcome send-off.
The show also inspired three spin-offs, CSI: Miami (2002-2012), CSI: NY (2004-2013) and CSI: Cyber (2015-2016).prevnext
E/R was a short-lived comedy starring George Clooney and Mary McDonell that ran one season with 22 episodes on CBS. No, that's not the ER that's really on this list.
The idea of a TV show set in an emergency room was much more successful as a drama. Michael Chrichton created ER, which ran on NBC from 1994 to 2009. It had 331 episodes in 15 seasons. Coincidentally, both Clooney starred on the show and McDonnell earned an Emmy nomination for a 2002 guest role.prev