This study was undertaken to evaluate the frequency and prognostic significance of p53 protein accumulation in uterine sarcomas. Immunostaining for p53 protein was performed on formalin-fixed, paraffin-embedded sections from 158 patients with verified uterine sarcomas using monoclonal p53 antibody (DO-1). Antigen retrieval was performed with microwave oven technique. Nuclear p53 protein accumulation was demonstrated in 45% of the cases, more often in carcinosarcomas (73%) than in leiomyosarcomas (38%) and endometrial stromal sarcomas (27%). A significant correlation was found between p53 protein accumulation and malignancy grade (P = 0.003), mitotic count (P = 0.007), and DNA ploidy (P = 0.007), but not to FIGO stage (P = 0.6). The 5-year survival was not influenced by level of p53 protein accumulation. In Cox multivariate analysis, free resection margins at primary surgery (P < 0.0001), tumor diameter (P = 0.002), malignancy grade (P = 0.0004), and age at diagnosis (P = 0.0001) were found to be of independent prognostic significance while p53 protein accumulation had no significance (P = 0.022). Our results indicate that p53 alterations may play an important role in the carcinogenesis of uterine sarcomas, but in our study p53 protein accumulation had no impact on prognosis.