Objective: To analyze the association between oocyte quality and decreased ovarian reserve (DOR) markers in young women undergoing controlled ovarian stimulation (COS). Methods: This retrospective study included 49 patients classified as having DOR based on anti-Müllerian hormone (AMH) levels, follicle-stimulating hormone (FSH) levels, or antral follicle counts (AFCs; <10). Images of all obtained oocytes were analyzed, and oocyte quality was classified according to maturity and morphology. The COS protocol utilized gonadotropin (FSH and/or human menopausal gonadotropin [hMG]) doses ranging from 150 to 300 IU/day. The Student’s t test or Mann-Whitney test was used to compare the groups. Spearman’s coefficients were estimated to verify the correlation between the administered dose of FSH/hMG and the number of mature oocytes. To evaluate the association between patient- and oocyte-related variables, logistic regression models were adjusted. Results: Women with DOR classified according to FSH level had more immature oocytes (P<0.001). Women with DOR according to AMH had fewer mature oocytes and increased basal FSH levels (P<0.001). Women with DOR according to AFC had an increased risk of abnormally shaped oocytes (P=0.035). Conclusion This study showed that DOR based on AMH levels, FSH levels, and AFC was associated with poorer quality oocytes in young women who underwent COS.