A group of 49 Mayo Clinic patients in whom the original diagnosis of lymphoma was made at splenectomy is reported. Systemic symptoms and pain were the commonest complaints and peripheral blood cytopenias were the major abnormal laboratory findings. The correct diagnosis was suspected in almost half of the patients prior to surgery. The 5-year survival rate for the entire group was 31%. The survival rate of 17 patients with localized lesions that were resected was considerably better than in those with residual tumor left after surgery. Patients of various histologic types of lymphoma with a follicular pattern of distribution tended to have a better prognosis than those with diffuse infiltration. The group with lymphocytic lymphoma had a 5-year survival rate of 60%, considerably higher than that for patients with lesions of other histologic types.