Updated

Amitabh Bachchan has played double role in following movies.

Bemisal (1982) - (Dr. Sudhir Roy and Adhir Roy),
Hum Kaun Hai ? (2004) - (Major Frank John Williams and Frank James Williams).

So Amitabh has played double / multiple roles in 15 movies (including 13 already listed).

Amitabh has acted in 5 movies, which has double role of some other actor. These movies are Amar Akbar Anthony (Jeevan), Besharam (Deven Varma), Akayla (Keith Stevenson), Hindustan Ki Kasam (Ajay Devgan), Ab Tumhare Hawale Watan Saathiyo (Bobby Deol).
In all, Amitabh has featured in 20 movies of this category (of having double / multiple roles).

Amiabh has acted double / multiple roles in 3 movies in year 1982 including Desh Premee and Satte Pe Satta, both already listed.
So, Amitabh has acted double / multiple roles in most number of movies (3) in a single year (1982).

Sanjay, I request you to retain current answers of this question which currently lists 9 actors tied with 2 movies each. This is also important information.
You may retain under separate question of 2 movies in single year.

Once again, thank you very much for keeping this important reference information updated.

RAAJA (1975) Rishi Kapoor twins

Updated.

@bhidesm & shuman
Thanks

How about South Indian movies?

Billa (Don Remake) 2009 telugu
Prabhas plays Billa & Ranga


Azhagiya Thamizh Magan 2007 tamil
Vijay plays 2 Roles Guru & Prasad

Anniyan 2005 tamil
Vikram plays a person with 3 personalities: Ambi, Remo and Anniyan

not sure if Kanthasamy 2009 tamil counts
Vikram plays CBI officer Kanthasamy and robinhoodlike Superhero/Rooster

This list is only limited to HIndi movies. But you are welcome to start another one for South films, although would that be limited to just a particular languagew or all South languages combined. Would be rather difficult to compile and maintain, I think.

OK. U can delete my posting if you want.
I won´t open a new thread because I don´t know why?

well done abba -- boman irani plays twin brothers

Updated.

jeetendra did father-son in a couple of films, did he not? (pyaasa sawan, farz aur kanoon, ???)
he also did some other double roles not yet captured in this thread i think.

'Pyaasa Sawan' added to the list. Not too sure of 'Farz Aur Kanoon'.

Humshakal(1992)-vinod khanna(look alikes)
Pramaatma)-mithun chakraborty(brothers)
Bin Phere Hum Tere(1979)-vinod mehra(twin brothers)

updated:-

Tahqiqaat (1993)-jeetendra(twin brothers)
Mawaali (1983) -Jeetendra(look alikes)
Aaj Ka Mahaatma (1976)-Randhir Kapoor(twin brothers)

Mawali (1983) jeetendra plays lookalikes who turn out to be twin brothers

Actually Mawaali was a remake of south indian movie starring Rajnikanth 'Pokiri Raaja'.

Left out the below movies as well:-

Paap Aur Punya(1974) - Shashi kapoor(twin brothers)
Dil Ka Raaja (1972)-Raaj Kumar(father/son)
Jaan Ki Baazi (1985)-Sanjay Dutt(Lookalikes)
Police Officer (1992)-jackie shroff(twin brothers)
Yeh Raaste Hain Pyaar Ke (2001)-Ajay Devgan(Lookalikes)

I'm not sure about Shatrughan Sinha's double role in Dhokebaaz or Jackie shroff in Allah Rakka....