Nonspecific immunotherapy with monthly intramuscular (IM) injections of Corynebacterium parvum has been investigated in patients with disseminated melanoma. Forty-nine patients were randomized to receive either imidazole carboxamide (DTIC) alone or DTIC plus C parvum. A 24% overall objective response rate was observed, with no significant difference between the response rate or survival of the two treatment groups. Immunologic studies revealed no significant difference between the two groups. One patient undergoing chemoimmunotherapy demonstrated profound pancytopenia which responded to cessation of therapy, but toxic reactions were otherwise minimal. No advantage was obtained by adding IM injected C parvum to standard chemotherapy in the treatment of disseminated melanoma.