What is the longest aired episode of a TV series?

The final of Muhte?em Yüzy?l (The Magnificent Century) is 157 minutes without commercials. The final episode is on Youtube and it is a historical fiction series according to Wikipedia.

It is very common for Turkish TV series for 2 hours or more each episode. The final episode of each season even lasts longer.

TV channels generally air a shortened version / recap of the previous episode first. This generally takes 1 hour. After that airs 2 to 3 hours of the show. Including the commercials a single episode takes around 4 hours each night.

Also there are nearly 40 episodes each season. Note these numbers are not exceptions, it is the current pattern for popular channels now in Turkey.

Others: Episodes are free on broadcaster's page (but in Turkish)

• Cesur ve Güzel episode 32 159 minutes
• Kara Sevda episode 74 (final) 148 minutes
• Istanbullu Gelin episode 16 145 minutes

The last episode of M*A*S*H, "Goodbye, Farewell and Amen" has a runtime of 121 minutes. See the Amazon product page for the DVD release of this single episode

Related Wikipedia article.

In the UK it is very common for 'serious crime drama' to run at 90 mins - there are far too many shows to list.

These, however all break the 90 minute barrier & are are all single story per episode crime dramas, not mini-series...

BBC shows have the advantage over all others in that there are no adverts.

Inspector Morse ran 33 episodes at between 98 – 105 mins [2hr inc ads]

Poirot similarly [lengths varied across 13 seasons from 50 - 102 mins]

The pilot episode of Blue Murder ran at 138 mins - but was actually broadcast in two parts.

Silent Witness runs at 120 mins - but most episodes are shown split over two consecutive days at 60m each.
Seasons 3, 4 & 5 apparently ran as full 2 hour episodes [no ads, BBC] - so this might be the winner.
I just discovered Wikipedia disputes the IMDB data, so I've demoted it.

Possibly the first to use the long format was Columbo which ran at various lengths from 73 - 98 minutes.

To my surprise, I found answer in the Guinness book of world Records. There was a record for record-breaking single shot episode by Indian television series C.I.D.

The story is interesting as the director put condition to channel that if he could break record for single shot episode, it should be telecast same way without any cuts and it was aired on Sunday, 7 November 2004 at 8:00 pm IST. This episode was 111 minutes. You can read full blog here.

The Slow Television phenomenon in Norway almost certainly takes the record here. They broadcast long uninterrupted shows, like a 7-hour train journey, or a yule log burning. The longest I can find on a quick perusal of the Wikipedia page was a 60-hour broadcast:

On 28–30 November 2014, NRK aired the 60-hour Hymnal - cover to cover. The show depicted about 200 choirs, including around 3,000-4,000 singers and soloists, performing the entire contents of the Church of Norway's national hymnal, published in 2013. Most of the performances took place live at Vår Frue Church in Trondheim, though some recorded performances came from 11 other sites such as Karasjok in northern Norway and Decorah, Iowa. The church was open throughout the show, and more than 16,000 visitors dropped in. A total of 2.2 million viewers tuned in at some point during the program, with an average of 87,000 at any one time.

Many of the early episodes of Taggart, a Scottish police drama series, were 2 hours long including adverts. The longest was 145 minutes.

https://en.wikipedia.org/wiki/List_of_Taggart_episodes#Series_9_.281993.29

Herman Wouk's "The Winds of War" (1983) is 14 hours 43 minutes (883 minutes) in seven episodes. Individual episodes range from 1.5-ish to 2.5-ish hours long. Episode 1, The Winds Rise, has a run time of 2:28:48 (148+ minutes). Episode 7 is about a minute shorter.

"War and Rememberance" is similar: 1620 minutes in 12 episodes. The first episode is 149 minutes.

Of fiction, these seem to be winners (so far).

I guess the "BBC Four Goes Slow" series technically counts as a TV series and each "episode" (although they are relatively unrelated to each other) are 1 to 3 hours in length (tour of the London National Gallery is the longest at 3 hours/180mins of a single episode - with no advert breaks as it's the BBC - and the shortest being an hour of birdsong)

The last episode of Season 9 of The X-Files lasted for 1 hour and 26 minutes (86 minutes). That is 91% more than the average episode (45 minutes).