Objective: To verify the association of obesity and infertility related to anovulatory issues. Methods: This case-control study was carried out with 52 women, aged 20 to 38 years, divided into two groups (infertile − cases − and fertile − control), seen at outpatient clinics, in the period from April to December, 2017. Results: We found significant evidence that obesity negatively affects women's fertility (p=0.017). The group of infertile women was 7.5-fold more likely to be obese than fertile women. Conclusion: Strategies that encourage weight control are indicated for women with chronic anovulation, due to hight metabolic activity of adipose tissue.