Objective: This study aimed to analyze maternal serum β-arrestin-1 and β-arrestin-2 concentrations in pregnant women complicated with gestational diabetes mellitus (GDM) and compare them with the normoglycemic uncomplicated healthy control group. Methods: A prospective case-control study was conducted, including pregnant women complicated with GDM between 15 February 2021, and 31 July 2021. We recorded serum β-arrestin-1 and β-arrestin-2 concentrations of the participants. Receiver operating characteristic (ROC) curves were used to describe and compare the performance of diagnostics value of variables β-arrestin-1, and β-arrestin-2. Results: The mean β-arrestin-1 and β-arrestin-2 levels were found to be significantly lower in the GDM group (41.0 ± 62.8 ng/mL, and 6.3 ± 9.9 ng/mL) than in the control group (93.1 ± 155.4 ng/mL, and 12.4 ± 17.7, respectively, p < .001). When we analyze the area under the ROC curve (AUC), maternal serum β-arrestin-1 and β-arrestin-2 levels can be considered a statistically significant parameter for diagnosing GDM. β-arrestin-1 had a significant negative correlation with fasting glucose (r = 0.551, p < .001), plasma insulin levels (r = 0.522, p < .001), HOMA-IR (r = 0.566, p < .001), and HbA1C (r = 0.465, p < .001). β-arrestin-2 was significantly negatively correlated with fasting glucose (r = 0.537, p < .001), plasma insulin levels (r = 0.515, p < .001), HOMA-IR (r = 0.550, p < .001), and HbA1C (r = 0.479, p < .001). Conclusion: β-arrestin 1 and β-arrestin 2 could be utilized as biomarkers in the diagnosis of GDM. The novel therapeutic strategies targeting these β-arrestins may be designed for the GDM treatment. [ABSTRACT FROM AUTHOR]