Gestational diabetes mellitus (GDM) is a common pregnancy-related complication and growth differentiation factor-15 (GDF-15) is involved in a number of diseases; therefore, the aim of the present study was to investigate the level and clinical significance of serum GDF-15 levels in patients with GDM. A total of 237 pregnant women at 20-24 weeks of gestation were selected and assigned to a normal pregnancy group (70 patients) and a GDM group (167 patients) according to the presence or absence of GDM. The general clinical data of the two groups were collected. Fasting plasma glucose, 1-h plasma glucose, 2-h plasma glucose, glycated hemoglobin, fasting insulin, 24-h urinary albumin and serum GDF-15 levels were measured. The results showed that the body mass index (BMI) of the GDM group was higher than that of the normal pregnancy group. Fasting plasma glucose, 1-h plasma glucose, 2-h plasma glucose, fasting insulin, glycated hemoglobin and GDF-15 levels and the positive rate of microalbuminuria were significantly higher in the GDM group compared with the normal pregnancy group. GDF-15 levels were positively correlated with BMI, fasting plasma glucose, glycated hemoglobin, homeostasis model assessment-insulin resistance and fasting insulin levels. Logistic regression analysis suggested that elevated GDF-15 levels are an independent risk factor for microalbuminuria. In conclusion, serum GDF-15 levels are strongly associated with GDM and elevated GDF-15 levels are an independent risk factor for microalbuminuria. Serum GDF-15 may act as a novel biomarker for predicting microalbuminuria in GDM patients.