['To assess the impact of endometriosis on the outcome of intracytoplasmic sperm injection (ICSI) outcome.', 'Retrospective case-control study which enrolled 1280 consecutive cycles of 834 couples of ICSI with ejaculated sperm. Among them, 973 cycles of 632 couples had resulted in embryo transfer (ET). The presence of endometriosis was noted in 110 consecutive cycles of 45 patients among which 78 cycles of 44 patients had resulted in ET. Data from endometriosis group were analyzed in subgroups of minimal-mild (49 ET cycles of 25 patients) and moderate-severe (29 ET cycles of 19 patients). The controls consisted of 1170 consecutive cycles of age-matched 771 couples. Of the controls, 588 couples had 895 cycles of ET. Main outcome measures were implantation and clinical pregnancy rates.', 'There were no differences in cycle and ET cancellation rates between control and endometriosis groups. The number of oocytes retrieved, fertilization and cleavage rates and the number and quality of embryos developed and transferred were similar among the groups. The implantation and clinical pregnancy rates were also comparable.'] Do the presence and extent of endometriosis effect clinical pregnancy and implantation rates in patients undergoing intracytoplasmic sperm injection?