Endometrial hyperplasia(EH) and endometrial carcinoma(EC) very in their biologic potential, which may be correlated with the histologic grade. Evaluation of cellular kinetics, which may prove to be another measure of predicting biologic behavior. Accessments of AgNORs and PCNA(proliferative cell nuclear antigen) indeces in 33 cases of EH including 16 cases of simple hyperplasia(SH), 8 of complex hyperplasia(CH), and 9 of atypical hyperplasia(AH), and 28 of EC including 7 of grade I, 12 of grade II, and 6 of grade III were performed. The results were as follows :I, 12 of grade II, and 6 of grade III were performed. The results were as follows : 1. AgNOR counts per glandular cells(Mean SD) were 2.7±0.2 in normal proliferative and 2.3±0.2 in secretory endometrium, and increased to 3.2±0.3 in SH, 3.5±0.3 in CH, to 5.4±0.4 in AH, and finally 6.9±0.5 in endometrioid carcinoma(grade I: 5.8±0.7, grade II: 6.7±0.6, grade III: 8.4±0.9). 2. PCNA indeces(percentages of nuclear positive cells of total cells of glands) were 16±14.2 in normal proliferative endometrium and 12±8.1 in secretory endometrium, and increased to 18.4±14.7 in SH, 21.6±17.8 in CH, 36.4±27.4 in AH, and finally 42.1±31.3 in EC(grade I: 38.3±23.2,grade II: 39.4±25.4, and grade III: 58.4±35.3). 3. DNA aneuploidy was detected in 4 cases of EC(40%), and tended to be more frequently found in poorer histologic grade. This data suggest that cell kinetic evaluation of EH and EC using AgNORs and PCNA is well correlated with histologic grade. And with the aspect of biologic potential, AH could be regarded as well differentiated EC.