Minimal and mild endometriosis (stages I/II) is frequently identified in subfertile patients, especially in case of unexplained infertility. The impact of those lesions on fecundity is still debatted and they have been considered as paraphysiological by some experts. In addition, they are heterogenous with variable spread, biological activity, induced inflammation and, sometimes, the presence of associated mild adhesions. Stages I/II endometriosis are the most frequent endometriotic lesions encountered in subfertile women. Reduced oocyte quality, anti sperm effects and, possibly, endometrial disorders appear as the most pertinent mechanisms involved. Spontaneous fecundity of women with minimal or mild endometriosis is reduced when compared to fecundity of women whose infertility is unexplained. Intra-uterine insemination with controlled ovarian stimulation improves fecundity. Laparoscopic ablation of endometriotic lesions modestly improves fecundity. This procedure has thus been recommended in view of the very small increased surgical risk. IVF is the most efficient method allowing to obtain pregnancy, with slightly reduced or similar results when compared to the performances of IVF in case of tubal infertility.