We report the cytogenetic and molecular findings in a malignant mixed Müllerian tumor of the uterus in a 65-year-old woman. Karyotypic analysis revealed a t(8;22)(q24.1;q12) as the sole abnormality in all 20 cells analyzed. Southern blot analysis of two positional candidate genes, MYC at 8q24, and EWS at 22q12, showed no genomic rearrangement. The finding of the t(8;22) as the only abnormality may be of etiologic significance.