Patients (153) with biopsy-proven primary systemic amyloidosis (AL) were evaluated for their response rate to alkylating agent-based chemotherapy. Twenty-seven of the patients (18%) responded. The serum creatinine concentration had an adverse effect on response rate (P = .05). In patients with nephrotic syndrome, a normal serum creatinine value, and no echocardiographic evidence of cardiac amyloidosis, the response rate was 39% (12 of 31). Five of 34 patients with amyloid cardiomyopathy responded. Two of these five are alive 10 years after diagnosis. None of the 18 patients with amyloid peripheral neuropathy showed regression of their disease. The median time to achieve response was 11.7 months. The median survival of the 27 patients was 89.4 months and 21 of 27 survived 5 years (78%). Eight patients remain alive with a minimum follow-up of 90 months. Seven died of acute leukemia or dysmyelopoietic syndrome, a presumed complication of melphalan therapy. In the group of 126 patients who showed no response to alkylating agent-based therapy, the median survival was 14.7 months and 9 (7%) survived over 5 years. All 126 patients have died. Alkylating agent-based chemotherapy for AL is beneficial in a subset of patients and a trial of chemotherapy is strongly recommended. Those patients who do respond demonstrate survival benefit.