The immunofluorescent localization of γ2, γ1, and γA immunoglobulins was determined in various hamster tissues. It was found that γA containing plasma or lymphocytoid cells predominated in submaxillary gland, jejunum, colon, gall bladder, and liver. Spleen contained similar numbers of different classes of immunoglobulin containing cells. Peyer's patch tissue was not stained with H chain specific antisera to γ2, γ1, or γA. However, an antiserum directed against γ2 H chains and L chains revealed a crescent of cells in the portion of tissue closest to the mucosa. It is suggested these may be γM containing cells. Liver and kidney specimens from "normal" animals revealed early portal cirrhosis and proliferative glomerulonephritis with basement membrane deposition of γ2. Urinary bladder and lung tissues did not stain with any of the antisera used.