Purpose: Malignant Mixed Mullerian Tumor (MMMT) of the uterine corpus is one of the very uncommon and the most lethal tumors in the uterus. The aim of this study was to evaluate the role of FDG PET in detecting distant metastasis and residual and/or recurrent disease. Methods: Ten patients who underwent FDG PET for detecting distant metastasis and recurrence were included. Focal FDG accumulation was regarded as abnormal. We also reviewed serum CA 125 levels, anatomical images, and histopathological examination. Results: Three patients of 10 FDG PET showed abnormal FDG uptake. One had high serum CA 125 levels and high fractions of carcinomatous element on histopathologic examination. FDG PET showed metastatic lesions in unexpected locations, which could not be detected by anatomical images. Another had normal serum CA 125 levels with high sarcomatous element and CT could only detect a few lesions. The other had high serum CA 125 levels and also had high carcinomatous element. Seven patients who had no abnormal uptake on FDG PET had no clinical evidence of recurrence during the follow up period (51.7¡¾12.2 months). The mean disease free intervals of these 7 patients were 36.4¡¾6.0 months. Two patients with abnormal findings had never become disease-free condition during the follow up period (6.0¡¾4.2 months. Conclusion: FDG PET could be a useful modality for unexpected distant metastasis and follow up tool in patients with MMMT. (Nucl Med Mol Imaging 2006;40(1):16-22)