The passive transfer of high levels of anti‐type II collagen antibody from mice with type II collagen‐induced arthritis may transfer arthritis to syngeneic recipient animals. However, the transfer of either arthritogenic or sub‐arthritogenic doses of polyclonal anti‐type II collagen antibody, or non‐arthritogenic monoclonal anti‐type II collagen antibody may protect mice against the subsequent induction of arthritis by type II collagen. A protective effect was also observed in mice given free native type II collagen intravenously before the administration of collagen in an arthritogenic protocol.