Endometrial adenocarcinoma is commonly seen in the perimenopausal and postmenopausal age groups. Certain medical conditions (such as diabetes, hypertension, and obesity) are often associated with development of this disease. Consequently, when irregular bleeding develops, a decision to sample the endometrium is often predicated on the patient's age and the presence of these associated conditions. Often, healthy young women receive empirical hormonal therapy for irregular bleeding without prior endometrial sampling. An unusual case of endometrial adenocarcinoma arising during lactation in a young healthy woman is presented.