OBJECTIVE: This study was designed to investigate prorenin and secreted frizzled-related protein 4 (SFRP4) levels in pregnancies with or without gestational diabetes mellitus (GDM). METHODS: A total of 76 pregnant women were included in the study. Thirty-five of the pregnant women were included in GDM group according to the results of oral glucose tolerance tests (OGTT) and 41 of them were included in the control group. RESULTS: In the group with GDM, SFRP4 value was found to be significantly higher than that of the control group (5.59 ± 3.32 ng/mL vs 4.05 ± 2.15 ng/mL; p = 0.017). Women with GDM had significantly higher serum prorenin levels compared with control group [737 (427-1339) pg/mL vs. 535 (376-725) pg/mL; p = 0.009]. There was a significant positive association between prorenin and SFRP4 levels in GDM (r = 0.91; p < 0.001) and control groups (r = 0.42; p = 0.002) and whole pregnancies (r = 0.75; p = 0.002). CONCLUSION: We have shown that prorenin and SFRP4 were significantly elevated in GDM patients when compared to healthy control group. Furthermore, we found that there was a positive correlation between prorenin and SFRP4.