Purpose Biochemotherapy improves responses in metastatic melanoma, but not overall survival, in randomized trials. We developed a maintenance biotherapy regimen after induction biochemotherapy in an attempt to improve durability of responses and overall survival. Patients and Methods One hundred thirty-three chemotherapy-naïve patients with metastatic melanoma without CNS metastases were treated at 10 melanoma centers. The biochemotherapy induction regimen included cisplatin, vinblastine, dacarbazine, decrescendo interleukin-2 (IL-2), and interferon alfa-2b with granulocyte-macrophage colony-stimulating factor (GM-CSF) cytokine support. Patients not experiencing disease progression were eligible for maintenance biotherapy with low-dose IL-2 and GM-CSF followed by intermittent pulses of decrescendo IL-2 over 12 months. Patients were observed for response, progression-free survival, toxicity, and overall survival. Results The response rate to induction biochemotherapy was 44% (95% CI, 35% to 52%; complete response, 8%; partial response, 36%; stable disease, 29%). The median number of biochemotherapy cycles was four, and the median number of maintenance biotherapy cycles was five. The median progression-free survival was 9 months, and the median survival was 13.5 months. The 12-month and 24-month survival rates were 57% and 23%, respectively. Twenty percent of patients remain alive (12 without disease), with median follow-up of 30 months (95% CI, 25+ to 45+ months). Thirty-nine percent of patients developed CNS metastases. The median times to CNS progression and death were 8 months and 5 months, respectively. Conclusion Maintenance biotherapy after induction biochemotherapy seems to prolong progression-free survival and improve overall survival compared with recent multicenter trials of biochemotherapy or chemotherapy. The regimen should be studied in a randomized clinical trial in patients with advanced metastatic melanoma. CNS progression remains a formidable challenge.