Objective To compare the in vitro fertilisation (IVF) outcomes of poor ovarian responders among women with laparoscopically diagnosed minimal-mild endometriosis (Group A), moderate-severe endometriosis (Group B) and those without endometriosis (Group C). The comparisons were made separately for age groups younger than 35 years and 35 years or older.Design Retrospective study.Setting A university-affiliated hospital in Guangzhou, China.Population 495 women younger than 35 years old and 543 women aged 35 or older who had poor ovarian response with or without laparoscopically diagnosed endometriosis.Methods Poor ovarian response (POR) was diagnosed using the Bologna criteria. First cycle parameters were analysed over the same period of time from January 2011 to October 2014.Main outcome measures The primary endpoint was the live birth rate per embryo transfer cycle. Secondary outcome measures were clinical pregnancy rate, cycle cancellation rate and miscarriage rate.Results In women aged 35 or older no differences were found among the three subgroups in terms of live birth rate, clinical pregnancy rate, cycle cancellation rate or miscarriage rate; in women aged younger than 35 years, the clinical pregnancy rates were 62.96, 45.45 and 43.27% for Groups A, B and C, respectively (P = 0.028). The live birth rate, cycle cancellation rate and miscarriage rate were not significantly different. Compared with the older group of women, the younger women had a significantly higher live birth rate (P < 0.001).Conclusions A woman's age is the most important factor governing the live birth rate with IVF. Endometriosis has no consistent impact on IVF outcomes in women with POR.Keywords Aging, assisted reproductive technology outcome, endometriosis, poor ovarian reserve, poor ovarian responder.Tweetable abstract Endometriosis has no negative impact on IVF outcomes in women with poor ovarian response.