Open Access was first defined by the Budapest Open Access Initiative following a meeting organized by the Open Society Institute/Soros foundations. The subsequent Open Access movement has had a large impact on the scholarly communications system. This is seen in the growing number of Open Access journals and institutional and subject-based repositories which have developed over the past five years. The reaction of publishers to the movement has been mixed with individual publishers (both commercial and non-profit) experimenting with the model while large publishers' associations have generally shown resistance. However, the movement continues to gain strength as research funding agencies adopt Open Access mandates to the research they support.