Objective: This study aimed to determine whether gestational diabetes mellitus (GDM) increases the risk of urinary tract infections (UTIs), including pyelonephritis, which can affect preterm birth rates and maternal morbidity. Design: A retrospective case-control study. Setting: The study was performed at Tzafon Medical Center, focusing on data collected from 2010 to 2021. Population or Sample: The study included 912 pregnant women who underwent urine culture testing during hospitalization, divided into 449 with positive urine cultures (UTI group) and 463 with negative cultures (control group). Methods: Women were grouped based on urine culture results, matched for age and year of testing. The primary exposure was the GDM rate in each group. Main Outcome Measures: The main outcomes were the incidence of GDM in women with UTIs versus those without and the association of multiple gestations, renal diseases, and thrombophilia with UTI occurrence. Results: GDM rates were 5% in both groups (23/449 in the UTI group and 22/463 in the control group; p = 0.80). Significant associations were found between UTIs and multiple gestations, renal diseases, and thrombophilia. Conclusions: GDM does not increase the risk of UTIs during pregnancy. Further prospective studies are recommended to confirm these findings.