Seven cases of malignant melanoma in the close relatives of children with osteosarcoma and chondrosarcoma are described. The association between certain childhood malignancies (adrenal cortical carcinoma, osteosarcoma, chondrosarcoma, retinoblastoma) and malignant melanoma is discussed and it is proposed that in certain families malignant melanoma may be another manifestation of the same gene defect which results in susceptibility to tumours characteristic of the SBLA cancer family syndrome.