Background: The molar and non-molar lesions are determined during histomorphological examination and treated as inconclusive. The establishing of a marker by immunohistochemical investigations could influence the accuracy of the morphopathological diagnosis. The aim is evaluation of p57 immunoexpression in the trophoblastic germ compartment in molar and non-molar pregnancies. Material and methods: Abortion products from 15 patients with hydatidiform mole, 18 pregnancies solved on social indications and 16 short-term disordered pregnancies were evaluated depending on the immunoexpresion of p57. Results: The hydatidiform mole was classified based on anti-p57 immunoexpression into: complete hydatidiform mole – 8 cases (negative immunoexpression or expression in ˂10% of villous cytotrophoblast) and partial hydatidiform mole – 7 cases (positive expression in ˃10% of the villous cytotrophoblast). Basal deciduous and extravillous cytotrophoblasts were positive in 100% of cases and served as internal control. Hepatocytes were used as negative control. In the control group, the positive immunoexpression was attested in >10% of cases in the villous trophoblast. Conclusions: Differential immunoexpression of p57 protein in the germinal cytotrophoblast allows subclassification of molar pathology into complete and partial forms, while not allowing the differentiation between partial hydatidiform mole and non-molar lesions. Immunohistochemical evaluation of p57kip2 protein in molar and non-molar pathology is useful in differential diagnosis as a complementary method.