Objective Hysteroscopy is frequently performed in infertile women and thought to improve pregnancy rates. The data obtained from studies searching the effect of hysteroscopy in in-vitro fertilization (IVF) cycles is variable. We aimed to evaluate the effect of hysteroscopy on the pregnancy outcomes of fresh and frozen-thawed embryo transfers done in the IVF cycles respectively. Material and methods We scanned the data of the 765 patients who had IVF treatment between January 2015 and July 2017 in an infertility center retrospectively. Of those, 586 patients were done fresh embryo transfer, 179 patients were underwent frozen-thawed embryo transfer (FET). Hysteroscopy was scheduled 2 months before the transfer by a single experienced surgeon. 101 patients in the fresh embryo transfer group and 44 patients in the FET group were underwent hysteroscopy. The pregnancy outcomes of the groups were compared respectively within their own group. Results The mean age was similar in patients within in the fresh and frozen-thawed embryo transfer groups (p= 0.418 and p=0.277, respectively). There was no statistically difference according to transferred embryo numbers in the fresh and frozen-thawed groups (p=0.218). We achieved 246 pregnancy in the fresh embryo group (44 patients were underwent diagnostic hysteroscopy while 202 did not, p= 0.516) and 79 pregnancy in frozen-thawed embryo group (20 patients were underwent diagnostic hysteroscopy while 59 did not, p= 0.711). There was no statistically difference according to pregnancy rate between the groups (p= 0.538). Conclusion Performing diagnostic hysteroscopy before fresh or frozen-thawed embryo transfer does not improve the pregnancy rates.