DaDa Online - Marcel Duchamp: Includes a biography, the text of "Apropos of Readymades" and some images.
Fresh Widow - Encounter with Marcel Duchamp: Site dedicated to the man who made art out of an urinal.
Marcel Duchamp - Olga's Gallery: Collection of artist's works with a biography and historical comments.
Tout-Fait - Marcel Duchamp Studies Online Journal: Journal focusing on the French-American artist Marcel Duchamp.
Understanding Duchamp - Retrospective: Presents artist's biography and images of his works.
University at Buffalo - Dada Without Duchamp / Duchamp Without Dada: A scholarly essay by Marjorie Perloff.