Combination studies of immunotherapy and DTIC chemotherapy for patients with malignant melanoma are described. At our institute the combination of bacillus Calmette-Guérin (BCG) with DTIC, or DTIC plus methyl-CCNU, has resulted in augmentation of remissions in areas regional to BCG immunization, prolongation of chemotherapy-induced remissions, and significant prolongation of survival compared to the use of DTIC chemotherapy without immunotherapy. Data from other centers have shown that augmentation of remissions for melanoma patients occurred when BCG was combined with DTIC, vincristine, and allogeneic tumor cells. Finally, another study has shown that DTIC combined with BCG has prolonged the disease-free interval and survival in melanoma patients with regional lymph node metastases. The potential inhibition of DTIC metabolism by BCG or Corynebacterium parvum is discussed.