AbstractA rapid, automated immunocytochemical staining method was developed for detection of lymphocyte surface markers with the Code-On Immuno/DNA Slide Stainer. Acetone fixed, frozen tissue sections from snap frozen lymph nodes and tonsils were stained for various B andT cell markers by the immunoperoxidase technique with commercially available antibodies and the Vectastain Elite kit. This system produced high quality, specific staining with substantial time and cost savings over manual processing. (The J Historechnol14:231, 1991)