AimsEarly identification of at-risk groups is an important step in preventing gestational diabetes and its subsequent side effects. This study aimed to evaluate the risk factors of gestational diabetes based on the International Association of Diabetes and Pregnancy Study Groups criteria in Ahvaz. Material and MethodsIn a cross-sectional case control study, 520 pregnant women involving life after gestational diabetes Ahvaz cohort study (LAGAs) were investigated for risk factors of gestational diabetes mellitus. ResultThe prevalence of overweight and obesity were 40% and25.8% in the GMD group and in 35.8% and 16.2% in the control group respectively (p = 0.002). According to NCEP-ATP III criteria, 16.9% of women with GDM and 6.9% of mothers in the control group had metabolic syndrome in first visit of pregnancy (p < 0.001. Logistic regression showed that there is a significant relationship between maternal age[OR = 1.05(95% CI, 1.01–1.10)] (p = 0.01), previous GDM [OR = 5.60(95% CI, 2.21–14.18)] (p = 0.001), positive family history of diabetes[OR = 1.86(95% CI, 1.19–2.94)] (p = 0.006), pre-pregnancy BMI [OR = 1.05(95% CI, 1.007–1.11)] (p = 0.04) and metabolic syndrome in first visit of pregnancy[OR = 2.34 (95% CI, 1.038–5.30)] (p = 0.04) with GDM. ConclusionFactors including maternal age, previous GDM, family history of diabetes, pre-pregnancy BMI reported in previous studies around the world. A significant association between metabolic syndrome in the first visit of pregnancy and GDM is novel finding of this study. Therefore screening of pre-pregnancy metabolic syndrome in women at risk of gestational diabetes is recommended.