Sentinel lymph node (SLN) mapping has changed the way of lymph node assessment and provided a minimal invasive option that lessens the negative effects of a full lymphadenectomy, has become a crucial tool in the treatment of endometrial cancer. Chronic lymphocytic leukemia (CLL) and endometrial cancer diagnosis at the same is a rare condition. This case report presents a 66‐year‐old woman admitting to the hospital with the complaint of postmenopausal bleeding. After hysteroscopic evaluation and Magnetic Resonance imaging confirming the endometrial cancer, total laparoscopic hysterectomy and bilateral salphingo‐ooferectomy with SLN mapping operation was planned. In the preoperative preparation she was also diagnosed with CLL. Considering the possible lymphatic obstruction, the risk of SLN mapping failure was foreseen, yet still the operation was performed as planned. This report will highlight a case where endometrial cancer and CLL were identified simultaneously, along with successful SLN mapping.