Endometriosis may be associated with infertility through a variety of mechanisms. Infertile couples where the woman has endometriosis should undergo semen analysis, assessment of ovulation and laparoscopic examination of the pelvis by a specialist to determine the severity of endometriosis. Couples with minimal or mild endometriosis may expect spontaneous conception rates of 5 to 10% per month, though fecundity declines with increasing female age and prolonged duration of infertility. Laparoscopic treatment of minimal/mild endometriosis may promote fertility, but the evidence is mixed and the size of the treatment effect is likely to be modest. Superovulation and intra-uterine insemination improves pregnancy rates, with the risk of multiple pregnancy and ovarian hyperstimulation syndrome. Couples where the woman has moderate/severe endometriosis have a low spontaneous conception rate. Surgical excision/ablation of endometriosis improves their chances of conception. In-vitro fertilization is a valid option for couples with any grade of endometriosis where other methods have failed or are deemed unsuitable. Large endometriotic cysts should be surgically treated prior to IVF to aid egg retrieval and avoid infective complications. Medical treatment of any grade of endometriosis in couples trying to conceive is not appropriate as it is contraceptive in effect and does not improve chances of conception after it is stopped.