The longest running TV show, obviously, has changed from time to time throughout the history of television. Then again, there isn't just one answer to "What is the longest running TV show?", as there are different factors to consider: time period, category of show, and even country. The longest running TV show, as it turns out, isn't always a single show.
In the United States, the longest running TV show is "Meet the Press". A TV show doesn't have to be a primetime special, it can be a news hour broadcast as well. Broadcasted by NBC, "Meet the Press" has been running for over 63 years, with the same amount of seasons under its belt.
The longest running animated series is "The Simpsons". Since December of 1989, "The Simpsons" has been producing relevant and humorous content for viewers every season it has aired. "The Simpsons", while often out-performed by animated shows such as "Family Guy", has yet to go unnoticed by the mainstream American viewer.
Different countries have different records. In the United Kingdom, the longest continuously-aired TV show is "Panorama", which has been running since 1953. Australian TV shows have been looking at "Four Corners", one of the nation's premiere journalistic programs, for its lead in tenure (since 1961).
Episode counting yields different results. Soap operas dominate the TV show rankings by number of episodes. The soap opera "Guiding Light" has 15,762 episodes with 57 seasons, while "As the World Turns" follows with over 13,858 episodes. Both of these shows ran from the early-middle 1950's to 2009 and 2010 respectively.
The longest running game show is "The Price is Right". Bob Barker's "The Price is Right" is a TV show that has been on air since September 4, 1972. As of the late 2000's, this show has aired over 7,300 episodes.
There are a good number of television programs that qualify as the longest-aired TV show, in their own regard. Not every TV show can make it for a couple of decades (such as "The Simpsons") let alone over half a century ("Meet the Press"). It's quite an honor to be the producer of any of these legendary television programs, or to have seen just why people love them so much.