The prognostic significance of the invasive type of carcinoma cells in endometrial carcinoma is not defined. We evaluated the prognostic significance of the invasive type, as well as the immunostains of p53, c-erbB-2, Ki-67 antigen and MDM2 in endometrial endometrioid adenocarcinoma. This prospective analysis comprised 112 patients with endometrioid adenocarcinoma of the uterine corpus who had undergone surgery and were traced for more than 5 years after the operation. They were divided into recurrence (16 patients) and non-recurrence (96 patients) groups. The invasive type of carcinoma cells was divided into expansile, mixed (expansile and infiltrative) and infiltrative pattern. The difference in the invasive type (P < 0.001) and p53 expression (P = 0.004) between the recurrence and non-recurrence groups was significant in the univariate analysis. Moreover, the invasive type was significant in the multivariate analysis (P = 0.004). In contrast, the difference in MDM2 expression, c-erbB-2 expression and the Ki-67 labeling index in both groups was not significant in the univariate analysis. The infiltrative pattern of the invasive type (P < 0.001) and p53 expression (P = 0.043) were significantly related to a poor prognosis in the Kaplan-Meier method using the log-rank test. In conclusion, the current study indicated that the infiltrative pattern of the carcinoma cells is a predictor for poor prognosis in endometrioid adenocarcinoma in the uterine corpus. It was also indicated that p53 immunostains are useful as a predictor, but Ki-67 antigen, c-erbB-2 and MDM2 stains are not.