Background. Endometriosis is nowadays probably the most frequent cause of infertility or subfertility and is revealed in approximately 30–40% of infertile women. The association between fertility and minimal or mild endometriosis remains unclear and controversial. Moderate and severe forms of the disease distort anatomical relations in the minor pelvis, resulting in infertility. The goals of endometriosis treatment are relief of pain symptoms, prevention of the disease progression and fertility improvement. Treatment of stages I and II endometriosis (according to the R-AFS classification) may be expectative, medical or surgical. In severely forms of the disease (stage III and IV) the method of choice is surgical treatment. Combined medical and surgical treatment is justified only in cases, in which the complete endometriotic tissue removal is not possible or recurrence of pain symptoms occur. Nowadays, laparoscopic surgical treatment is the golden standard being the diagnostic and therapeutic tool during the same procedure. The aim of this study was to evaluate the fertility rate after surgical treatment of different stages of endometriosis. Patients and methods. In prospectively designed study 100 infertile women were included. The only known cause of infertility was endometriosis. In group A there were 51 patients with stage I and II endometriosis, whereas in group B there were 49 patients with stage III and IV of the disease. Endometriosis was diagnosed and treated laparoscopically. Endometriotic implants were removed either with bipolar coagulation or CO2 laser vaporisation, whereas adhesions were sharp or blunt dissected, and endometriomas stripped out of ovaries. Pregnancy rates were calculated for both groups of patients, and statistically compared between the groups. Results. Mean age of patients was 29.25 (SD ± 4.08) years and did not significantly differ between the groups of patients (29.5 years in group A and 29 years in group B). In group A 31 (60.8%) out of the 51 patients conceived spontaneously within 24 months after surgery. In group B 30 (61.2%) out of the 49 patients conceived spontaneously after surgery. The difference in pregnancy rates between the groups was not statistically significant. Conclusions. Surgical treatment of endometriosis in infertile patients is by all means effective and most appropriate, although some have not confirmed its value in patients with minimal or mild endometriosis comparing it with the no-treatment protocol. The limitations of this study should be considered. The main drawback is its design: the trial was not a randomised controlled one. We advocate that endometriosis once diagnosed must be surgically treated, to prevent progression of the disease at least. Endometriosis appears to progress in two-thirds of patients within a year from the diagnosis, and it is impossible to predict, in which patients it will progress. It would be unethical, and even unprofessional not to remove even the smallest endometriotic implants when the disease is confirmed by laparoscopy.