The value of chromosomal analysis is well established in human hematologic neoplasms. In contrast, the relation between chromosomal abnormalities and clinical outcome in solid tumors in humans has received little study. We undertook this study to determine whether chromosomal abnormalities could provide information on the survival of patients with malignant melanoma. Chromosome-banding analysis was performed on tumor-biopsy samples from 62 patients with metastatic melanoma, and recurring cytogenetic abnormalities were correlated with survival. Patients with structural abnormalities of chromosome 7 or 11 had significantly shorter survival than patients without these abnormalities. We conclude that cytogenetic analysis may provide useful prognostic information about patients with metastatic melanoma.