Abstract Objectives: The aim of the study was to assess the correlation between the activity of thymidine phosphorylase (TP) and the platelet derived-endothelial cell growth factor (PD-ECGF) expression in endometrial carcinoma. Methods: The study group consisted of 40 tissue samples taken from patients with endometrial carcinoma, who underwent surgery in First Clinic of Gynecology and Oncologic Gynecology of Medical University in Lodz. The control tissue samples were taken from patients who were operated on for non-oncologic reason. The activity of TP was measured by the spectrophotometric method in the cytosol of tumor cells, and the immunohistochemical staining of PD-ECGF was performed in the same tumors. The results of TP activity were compared with the microvessel density (MD) assessed by immunohistochemical analysis and with clinico-pathological features like tumor grade and FIGO stage. Result: A positive correlation between the enzyme activity and expression of TP/PD-ECGF protein was found. Moreover, a significantly higher TP activity was confirmed in malignant tumors from endometrial cancer patients when compared to the controls. A positive correlation between the enzyme activity and MD was also stated, but there was no connection to the grade of tumors and FIGO stage. Since the TP activity proved to be related to PD-ECGF expression and angiogenesis, we can state that TP seems to be an active form of PD-ECGF growth factor in endometrial carcinoma. This is in agreement with the results of many publications on other malignancies. The proper modulation of this activity may be useful in adjuvant therapies.