Introduction: Fifteen to twenty percent of the patients with complete hydatidiform mole transform malignancy into gestational trophoblastic tumors. The marked proliferation of trophoblastic cells is one of the characteristics that determines high risk for the occurrence of post-hydatidiform mole malignancy. The objective of the study was to analyze the histopathologic feature of the marked proliferation of trophoblastic cells as a role in posthydatidiform mole malignancy that can be used as a determinant of the risk of malignancy post-hydatidiform mole. Methods: The method of the study was analytical observational with a case-control study design. The data were taken retrospectively from medical records of patients with a post-complete hydatidiform mole malignancy and patients who do not develop postcomplete hydatidiform mole malignancy (n = 34). The study took place in the