Clinical cases of ectopic location of pregnancy are relevant and interesting both from a scientific and practical point of view. Particular caution in the development of ectopic pregnancy is associated with the possibility of its progression in some localities up to the second trimester or until its termination. This complication of the gestational period is very dangerous, as it can lead to profuse bleeding and death of a woman. The article presents a rare case of ectopic location of a fetal egg — pregnancy in the abdominal cavity after in vitro fertilization and embryo transfer. A 38-year-old woman M. turned to the department of assisted reproductive technologies (ART) with complaints of pain in the lower abdomen, after which she was sent for ultrasound, where a tubal pregnancy was diagnosed on the left. Urgently hospitalized in the gynecological department of the BU «Presidential Perinatal Center» of the Ministry of Health of the Chuvash Republic. Upon admission, the general condition is satisfactory. Objectively: the abdomen is soft, moderately painful on palpation in the left iliac region. Gynecological status: a formation without clear contours is palpated on the left. Surgical treatment was performed: laparoscopy, adhesiolysis and removal of the fetal egg. Hemorrhagic effusion in the amount of 30 ml was determined in the abdominal cavity. The uterus is of the correct shape, measuring 5×4×3 cm. The left ovary is 3×2×2.5 cm in size, without pathology. The left fallopian tube is visible throughout, 12 cm long, the shape is not changed, the fimbriae are pronounced, there are no peritubar adhesions. On the peritoneum between the tube and its own ligament of the left ovary, a 15×15 mm cyanotic-purple formation was found, covered with dark blood clots, contact bleeding. According to the results of the pathologic and histological examination, the elements of the fetal egg were determined: chorionic villi with initial signs of angiogenesis, extra-fibrous trophoblast, decidual cells and blood, fibrinoid zones and single hyperchromic cells of invasive trophoblast, a section of the peritoneum with signs of fibrinoid necrosis. Conclusion. Thus, women whose pregnancy occurred after the use of assisted reproductive technologies should be especially carefully examined in the early stages of gestation. Since early diagnosis of atypical localization of the fetal egg and timely surgical intervention will avoid the development of dangerous complications, eliminate the threat to the life and health of the patient.