Epididymal spermatic granulomas from five adult (greater than 4 years old) rams from a commercial flock were evaluated by quantitative histologic methods. Sections were stained for isotype specific immunoglobulin (Ig)-containing cells or specific lymphocyte subsets, as indicated by plasma membrane staining with monoclonal antibodies (MoAb). For the purpose of analysis, individual spermatic granulomas were allocated to one of three groups (early, resolving, or intermediate) on the basis of histologic examination. Ig-containing cells were most prevalent in early spermatic granulomas, and IgG-containing cells predominated in all spermatic granulomas regardless of their presumed age. IgM immunoglobulin-containing cells were the next in prevalence, and IgA-containing cells were infrequent. Assessment of lymphocyte subsets confirmed that lymphocytes present were of both T- and B-cell lineage and were well represented in all spermatic granulomas. CD4+ (MHC Class II-restricted "helper") T-cells were more prevalent in early spermatic granulomas than in intermediate or resolving types, while CD8+ (MHC Class I-restricted, "cytotoxic/suppressor") T-cells were more prevalent in spermatic granulomas of the intermediate type. These results suggest that in addition to an essentially foreign body reaction to extravasated spermatozoa, both local production of antibody and accumulation of a variety of B- and T-lymphocytes are present in ovine spermatic granulomas.