© 2022 Informa UK Limited, trading as Taylor & Francis Group.In our retrospective cohort study, we aimed to determine the role of endometrial thickness (ET) in isolated male factor infertile women in vitro fertilisation/intracytoplasmic sperm injection (IVF/ICSI) fresh embryo cycles. The patients were classified as having an endometrial thickness of <7 mm (n: 80), 7–9.9 mm (n: 335), 10–14 mm (n: 579) and >14 mm (n: 50) according to their ETs on the human chorionic gonadotropin (hCG) day. The overall clinical pregnancy rate was 37.4%, and no significant difference was found between the groups (p =.262). There was no significant difference between live birth rates (p =.094), but the highest pregnancy (46%) and live birth (34%) rates were found in the group with >14 mm ET. The increase in ET in IVF cycles increases pregnancy rates, albeit partially. When it is desired to determine a cut-off value, it can be said that pregnancy rates increase significantly in thicknesses of 14 mm and above.Impact StatementWhat is already known on this subject? When the literature is examined, many studies conclude that clinical pregnancy rates increase with the increase in endometrial thickness (ET) in IVF cycles, but there are also studies that argue the opposite. There is no study in the literature investigating the effect of ET on clinical pregnancy rates in patients with isolated male factor infertility. What do the results of this study add? In support of the literature, an increase in ET was found to be associated with an increase in clinical pregnancy rates, regardless of male and female factors. Although pregnancy occurs in thin endometriums, abortion rates are undesirably high. What are the implications of these findings for clinical practice and/or further research? Although the risk of abortion is high in thin endometriums, live birth rates are satisfactory. As a result, thin endometrium does not require cycle cancellation.