Nine cases of malignant human salivary gland tumors cultured in vitro were subjected to detailed cytogenetic analysis with G-banding. Together with observations from three earlier published cases, the results of 12 cases were surveyed: five adenoid cystic carcinomas, three acinic cell tumors, three adenocarcinomas, and one mucoepidermoid carcinoma. All tumors had stemlines in the diploid-near-diploid mode. The most consistent changes among the adenoid cystic carcinomas were stem lines and/or variant cells with anomalies affecting the terminal part of 6q (i.e., 6q 16-25). Deviations affecting the Y chromosome (losses) and, to a lesser extent, #6 (structural changes) and #8 (gains) characterized the early karyotypic evolution in acinic cell tumors. Two of the three analyzed adenocarcinomas showed stemlines or variant cells with loss of gonosomes. The karyotypic features of the different tumor types, including primary changes, evolutionary characteristics, and progressional pathways, are discussed. The cytogenetic relationships between benign and malignant salivary gland tumors also will be considered.