Antigen-antibody complexes derived from rabbit antibodies bind to mouse spleen lymphocytes. This binding was detected by the inhibition of reverse immune cytoadherence (RICA), a technique detecting surface γ globulin and suggests that these complexes bind to γ globulin carrying B-cells. Complement is not a requirement for binding. Complexes made from 5S bivalent antibodies do not bind nor does 7S antibody or normal γ globulin. Chemically produced microaggregates of ferritin show no binding. Mouse complexes made with mouse γG (7Sγ2a) antibodies also bind to mouse spleen cells. Fc fragments isolated by papain digestion of rabbit antibodies also inhibit RICA and Fc crystals can form around the mouse spleen lymphocytes. Fc from normal rabbit γ globulin is less inhibitory. These results are presented as evidence of the existence of a receptor, provisionally called the Fc receptor, on the surface of mouse spleen lymphocytes which are probably B-cells.