Which TV Shows Have Aired the Most Original Episodes?

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The longest-running American prime-time series shows no sign of wrapping up, as Fox renewed “The Simpsons” for its 23rd season on Thursday (Oct. 11). While it may be the longest running, the title of most original episodes goes to a different show - “Law & Order.”

When the TV drama “Law & Order” aired its final episode, it marked the end of an era – the show ran for 20 consecutive seasons. The fact that the series lasted this long might be considered an achievement. Never a ratings powerhouse , it finished in the Nielsen rating's Top 10 only once, ranking No. 7 in its 12th season. But its immense popularity in syndication made it a lucrative property for NBC.

Simply put, TV shows simply don’t last this long anymore.

The television landscape has become increasingly fragmented by cable channels and online entertainment options. Gone are the days when shows would get a season or two to find their audience, like "Cheers" and "Seinfeld" did.

The high costs of producing network television means that series run for fewer episodes. Most scripted programs today produce no more than 22 episodes per season. It wasn’t uncommon for older shows like “Bonanza” and “Bewitched” to churn out more than 30 episodes a season.

Here are the five American prime-time scripted TV series that produced the most episodes:

1. “Gunsmoke” (1955-75): 635 episodes

This classic Western’s prodigious output will likely never be matched. James Arness starred as Marshall Matt Dillon in all 20 seasons, another industry record. The show was TV’s top-rated show from 1957 to 1961, and never finished out of the Nielsen Top 30.

The show’s original outdoor sets in Simi Valley, Calif., were later used on another long-running show, “Little House on the Prairie.”

2. “Lassie” (1954-73): 588 episodes

One of the first true crossover stars, “Lassie” began as a movie star, appearing in seven films for MGM before moving on to small-screen stardom. “Lassie” aired on CBS its first 17 seasons, and won two Emmys for its family-friendly messages.

Six different dogs portrayed Lassie, with Baby lasting the longest , from 1960 to 1966.

3. “The Simpsons” (1989-present): 463 episodes

Lost in all the attention given to the cancellation of “Law & Order” is the fact that it wasn’t even the longest-running scripted series on the air in 2010. Matt Groening’s beloved animated series completed its 21st season, making it the longest-running American prime-time series.

“The Simpsons” has won 25 Emmys and a Peabody Award, and was named the 20th Century’s Best TV Show by Time Magazine. Writer John Swartzwelder has written the most “Simpsons” episodes, 60 in all.

4. “Law & Order” (1990-2010): 455 episodes

The legal show was a cornerstone of NBC’s prime-time lineup for two decades, but it was supposed to debut on Fox. However, Fox executives didn’t feel it was a good fit for the network of “Married with Children” and “In Living Color,” so they passed.

The show inspired four spin-offs under the “Law & Order” banner, “Criminal Intent,” “Special Victims Unit,” “Trial By Jury” and “Law & Order: Los Angeles."

5. “The Adventures of Ozzie & Harriet” (1952-1966): 435 episodes

The quintessential, all-American family sitcom, “Ozzie & Harriet” started out as a radio program. After 402 episodes, it moved to television .

Ozzie and Harriet Nelson, along with their real children David and Ricky, became instant stars. Ricky, in particular, became one of the first teen idols of the TV generation. “The Adventures of Ozzie & Harriet” aired in black and white for all but its 14th and final season.

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