BACKGROUND The aim of this study was to evaluate adipokines concentration and insulin resistance according to maternal age or obesity at pregnancy and weight change at diagnosed gestational diabetes mellitus (GDM) in pregnant women with GDM. METHODS This study included 57 pregnant women who were diagnosed with GDM at 24 to 28 weeks of gestation. The subjects were classified into two or three groups according to pre-pregnancy body mass index (BMI, <25 kg/m² vs. ≥25 kg/m²), maternal age at pregnancy (<35 years old vs. ≥35 years old), and weight change during pregnancy at screening for GDM (weight change below, within, and in excess of the recommended range). They were respectively compared in each group. RESULTS Leptin, homeostasis model assessment of insulin resistance (HOMA-IR), and HOMA2-%B were increased in the group with pre-pregnancy BMI ≥25 kg/m². Leptin and HOMA-IR were positively correlated with BMI both before pregnancy and at screening for GDM. There were no significant correlations between HOMA-IR and adipokines. HOMA-IR showed positive correlation with HOMA2-%B and negative correlation with HOMA2-%S. CONCLUSIONS Leptin and HOMA-IR at diagnosed GDM were increased in the GDM patients with obesity before pregnancy. They were positively correlated with BMI both before pregnancy and at screening for GDM. The effect of maternal age at pregnancy and weight change during pregnancy at GDM screening on adipokines and insulin resistance might be less pronounced than the effect of maternal obesity.