- Sherlock Holmes (2009) .... Sherlock Holmes
- The Soloist (2009) .... Steve Lopez
- Tropic Thunder (2008) .... Kirk Lazarus - Hot LZ
- The Incredible Hulk (2008) (uncredited) .... Tony Stark
- Iron Man (2008) .... Tony Stark
- Charlie Bartlett (2007) .... Principal Nathan Gardner
- Lucky You (2007) .... Telephone Jack
- Zodiac (2007/I) .... Paul Avery
- Fur: An Imaginary Portrait of Diane Arbus (2006) .... Lionel Sweeney
- A Scanner Darkly (2006) .... James Barris
- The Shaggy Dog (2006) .... Dr. Kozak
- A Guide to Recognizing Your Saints (2006) .... Dito
- Good Night, and Good Luck. (2005) .... Joe Wershba
- Kiss Kiss Bang Bang (2005) .... Harry Lockhart
- Game 6 (2005) .... Steven Schwimmer
- Eros (2004) .... Nick Penrose (segment "Equilibrium")
- Gothika (2003) .... Pete Graham
- The Singing Detective (2003) .... Dan Dark
- Whatever We Do (2003) .... Bobby
- Lethargy (2002) .... Animal Therapist
- Auto Motives (2000) .... Rob
- Wonder Boys (2000) .... Terry Crabtree
- Black and White (1999/I) .... Terry Donager
- Bowfinger (1999) .... Jerry Renfro
- Friends & Lovers (1999) .... Hans
- In Dreams (1999) .... Vivian Thompson
- U.S. Marshals (1998) .... Special Agent John Royce
- The Gingerbread Man (1998) .... Clyde Pell
- Hugo Pool (1997) .... Franz Mazur
- Two Girls and a Guy (1997) .... Blake
- One Night Stand (1997) .... Charlie
- Danger Zone (1996) .... Jim Scott
- Restoration (1995) .... Robert Merivel
- Mr. Willowby's Christmas Tree (1995) (TV) .... Mr. Willowby
- Home for the Holidays (1995) .... Tommy Larson
- Richard III (1995) .... Lord Rivers
- Only You (1994) .... Peter Wright
- Natural Born Killers (1994) .... Wayne Gale
- Hail Caesar (1994) .... Jerry
- Short Cuts (1993) .... Bill Bush
- Heart and Souls (1993) .... Thomas Reilly
- Chaplin (1992) .... Charles Spencer Chaplin
- Soapdish (1991) .... David Seton Barnes
- Too Much Sun (1990) .... Reed Richmond
- Air America (1990) .... Billy Covington
- Chances Are (1989) .... Alex Finch
- True Believer (1989) .... Roger Baron
- That's Adequate (1989) .... Albert Einstein
- 1969 (1988) .... Ralph Carr
- Rented Lips (1988) .... Wolf Dangler
- Johnny Be Good (1988) .... Leo Wiggins
- Less Than Zero (1987) .... Julian
- The Pick-up Artist (1987) (as Robert Downey) .... Jack Jericho
- America (1986) .... Paulie Hackley
- Back to School (1986) .... Derek
- "Mussolini: The Untold Story" (1985) TV mini-series (as Robert Downey) .... Bruno Mussolini
- Weird Science (1985) (as Robert Downey) .... Ian
- Tuff Turf (1985) (as Robert Downey) .... Jimmy Parker
- Deadwait (1985)
- Firstborn (1984) .... Lee
- Baby It's You (1983) .... Stewart
- Up the Academy (1980) (uncredited)
- Greaser's Palace (1972) (uncredited)
- Pound (1970) (as Bob Downey) .... Puppy
jan 10 2010 ∞
jan 10 2010 +
jan 10 2010 +