Nine malignant mesonephric tumors were obtained from the consultation files of one of the authors (J.P.) over a 13-year period (1988-2001). There were 4 adenocarcinomas (ACs) and 5 malignant mixed mesonephric tumors (MMMTs). The ACs were found in the cervix (3) and vagina (1). The MMMTs involved the uterus (1), cervix (3), and vagina (1). Most patients presented with abnormal vaginal bleeding. The 4 patients with mesonephric AC ranged in age from 24 to 54 years (mean, 41 years). The tumors measured 2 to 6 cm (mean, 3.7 cm). Two ACs were stage I and two were stage II. Two of the three patients with follow-up information were alive without clinical evidence of disease at 3 and 11.5 years, and the other was alive with recurrent tumor 8.5 years postoperatively. The 5 patients with MMMTs ranged in age from 37 to 62 years (mean, 49 years). The mean size of four tumors was 5.2 cm (range, 3.5-8 cm). The uterine MMMT infiltrated the entire myometrial wall extending to the endometrial cavity where it resembled an endometrial polyp. Although the most common histologic pattern in the current series was the glandular (ductal) pattern, retiform, tubular, and solid growth patterns were also encountered. Among the MMMT subgroup, the sarcomatous component was homologous in 3 cases (endometrial stromal or spindle cell) and heterologous in the other 2 cases (skeletal muscle and cartilage). Of the 4 patients with follow-up information available, 1 (stage II) died of disease 7 months after surgery, another (stage IV) was alive with bone metastases at 3.3 years, and the other 2 patients (stages IB and IC) had no clinical evidence of disease at 1 and 3.7 years, respectively. Evidence of mesonephric hyperplasia was found in 5 (42%) cases. The MMMT that arose in the corpus presented as an endometrial polyp. In this case, histologic differential diagnosis includes serous carcinoma, endometrial stromal sarcoma, and uterine tumor resembling ovarian sex cord-stromal tumor. Immunostainings are not helpful. Mesonephric ACs often present in early stage and have better prognosis than their müllerian counterparts. Surgery alone appears to be the treatment of choice. In contrast, MMMTs may present in advanced stage and are aggressive tumors, similar to malignant mixed müllerian tumors.