About.com: Mark Ruffalo talks about "XX/XY.": Interview with the actor about his role in the dramatic romance co-starring Kathleen Robertson and Petra Wright.
Hollywood Bitchslap: Mark Ruffalo - Official Busiest Actor of 2004: Paul Zimmerman talks with the actor about his career.
IBaller.com: Mark Ruffalo: Thumbnailed photograph gallery, free desktop wallpapers, and filmography.
IMDb: Mark Ruffalo: Filmography, awards, biography, agent, discussions, photos and news articles for the actor.
Independence: The Mark Ruffalo Fanlisting: Fan site includes a biography, fan forums, filmography, screen captures and fun facts.
Star Chat: A Conversation with Mark Ruffalo: Bonnie Laufer talks with the actor about starring opposite Meg Ryan in the erotic thriller "In the Cut."
The Journal News: Invisible No More: William Booth talks to the actor about his career upturn.