Sazae-san has 6367+ episodes currently and it is still ongoing. Doraemon has 2189 episodes currently and ongoing. If you want to know next you could check it out in here: http://en.wikipedia.org/wiki/List_of_anime_series_by_episode_count
:)
Metropolis
The longest running cartoon in history is Japan's Sazae-San, it began in October 1969 & has been airing ever since.
"The Mousetrap" by Agatha Christie is recognized as the longest running play in the world. It premiered in London's West End in 1952 and has been running continuously ever since.
..one piece
Phantom of the Opera, it is the longest running show in the history of Broadway and is still running! For tickets go to: www.ticketmaster.com
Oxfam is the longest running charity
It's never become the longest running prime time series, nor will it ever earn that accolade.The Simpsons is the longest running American animated program & the longest running prime time scripted comedy & the longest running prime time American sitcom but the title of simply 'the longest running prime time series' belongs to The Hallmark Hall of Fame which has been airing for 64 seasons [& still does] followed by Walt Disney Presents which has been airing for 54 seasons [& still does].If you want to narrow it down to weekly series, 60 minutes is the longest running prime time series debuting in 1968.
Wild Kingdom is the longest running animal based TV show. It's original run was 1963-1988 (25 years), then it was revived in 2002 and remains on the air today (12+ years) as of 02|2014... so a total of 37 years & counting.
What ever anime you like
The longest song ever in the USA was 75 minutes
one piece
Detective Conan Detective Conan is in no way the longest ongoing anime or manga series. Not even close. Sazae-san is the longest ongoing anime and Chiisana Koi no Monogatari is the longest ongoing manga.