Background: The role of embryo transfer (ET) in the success of in vitro fertilization/intra cytoplasmic sperm injection treatment is not well understood. In the present study we classified ET technique as difficult and easy types according to certain strict criteria, and compared the pregnancy outcome of the two ET types. Methods: This study was performed retrospectively on 295 infertile patients undergoing 308 embryo transfer cycles during May 2006-March 2007 in Mashhad IVF center.These cycles were divided into two groups. Group I had an easy embryo transfer (n=248) and group II had a difficult embryo transfer (n=60). The ET was considered as easy if the catheter insertion was successfully achieved without difficulty or needed slight manipulations of speculum or outer sheath of the catheter. ET was considered as difficult if slight maneuvers did not result in successful catheter insertion, tenaculum was used, or there was a need to use rigid catheters. Observation of beating fetal heart in a gestational sac of 6-7 weeks considered as positive pregnancy. Comparison of the pregnancy outcome between both groups was performed by using Student t test and Chi-square test. The results were shown as X2±SD. P value<0.05 was considered statistically significant. Results: The differences between two groups regarding age, number of follicles ≥ 14 mm, number of retrieved oocytes, and number of transferred embryos were not significant (P>0.1). The total number of pregnancies was 55 (17.9%): 48 (19.4%) in group I and 7 (11.7%) in group II. The difference was not significant (P =0.163). Conclusion: Although the rate of positive pregnancy with easy ET was higher than difficult ET, there was no significant difference between the two groups (P =0.163). This may be due to the type of classification of easy and difficult, or fewer patients.