Sixty-nine salivary gland pleomorphic adenomas were fully karyotyped by G-banding including 40 tumors previously reported. The cytogenetic results allowed to distinguish between three major chromosomal subgroups characterized by either an apparently normal karyotype or by rearrangements of chromosome 8q12 or by rearrangements of chromosome 12q14-15. Significant correlations of these karyotypic groups with the age of the patients and histologic subgroups of the pleomorphic adenomas were found. Furthermore, our analysis revealed that the three main cytogenetic subgroups showed an uneven geographical distribution. Based on these results we have concluded that the cytogenetic groups represent different etiologic entities.