To evaluate whether laparoscopic excision of endometrioma exerts a qualitative effect on ovarian function. A retrospective analysis of oocytes retrieved in 25 cycles of 21 patients undergoing IVF treatment with controlled ovarian stimulation. The number of oocytes recovered from ovaries with a history of excision of endometrioma (E-Ov) were compared to those from contra-lateral healthy ovaries (H-Ov) as for the analysis of a quantitative effect of surgery. As for the analysis of a qualitative effect, 55 oocytes from E-Ov were compared to 128 oocytes from H-Ov in terms of normal fertilization rate and the rate of top-quality embryos per normally fertilized eggs. Furthermore, 10 embryos derived from oocytes recovered from E-Ov were compared to 24 embryos derived from oocytes from H-Ov in terms of clinical and on-going pregnancy rates per embryos in 34 single embryo transfer cycles. Mean number of oocytes recovered from E-Ov was significantly smaller than that from H-Ov (2.2 ± 2.0 vs. 5.1 ± 3.3, P = 0.009). There was no difference between oocytes from E-Ov and H-Ov as for normal fertilization rate (63.6% vs. 69.5%, P = 0.43) and the rate of top-quality embryos (40.0% vs. 49.0%, P = 0.34). Clinical and on-going pregnancy rates per embryos were also similar in embryos derived from oocytes recovered from E-Ov and H-Ov (40.0% vs. 25.0%, P = 0.39 and 20.0% vs. 20.8%, P = 0.96). The quality of oocytes recovered from the ovary with a history of laparoscopic excision of endometrioma is not inferior to the quality of oocytes from contra-lateral healthy ovary.