Three patients with a mean age of 69 years presented with endometrioid carcinoma of the prostate between 1995 and 2000. With a mean follow-up of 17 months, 2 patients are alive without metastases and 1 has died from another cause. Endometrioid carcinoma represents less than 5% of all prostate cancers. Its histological origin has been the subject of controversy for a long time. The clinical presentation is often unusual and the natural history is considered to be more aggressive than that of the glandular form of prostatic cancer. Endometrioid carcinoma of the prostate is not derived from Müllerian structures, but from prostatic tissue. It is an unusual form of prostatic cancer, whose clinical course and treatment are the same as those of adenocarcinoma.