The main objective of this retrospective study is to evaluate the question of whether it is necessary to perform surgery for patients who develop an acute abdomen after methotrexate administration in cases of tubal ectopic pregnancy. A total of 26 women with tubal ectopic pregnancy who required emergency surgical evaluation after a single dose of methotrexate treatment were included. The surgical findings were tubal abortion (10 cases, 38.4%); tubal rupture (12 cases, 46.2%) and tubal haematoma (4 cases, 15.4%). The average time for initiation of severe abdominal pain following single dose methotrexate treatment was 6.12±2.10 days (range, 210). The most common site of implantation was isthmus (50.0%) and 38.5% (five patients) of the patients had tubal abortion from this part of the tube, while 46.1% of women (six patients) with isthmic localisation had a tubal rupture. Following medical treatment of ectopic pregnancy, surgery may be an option in the presence of symptoms/signs of acute abdomen (in the presence or absence of haemodynamic instability) and free pelvic fluid on sonography for only patients with isthmic tubal ectopic pregnancy, or if the isthmic localisation of tubal ectopic pregnancy is suspected on sonography. © 2010 Informa Healthcare USA, Inc.