ABSTRACT. Leptin (LEP), a protein that plays a fundamental role in the metabolism of energy reserves, and the solute carrier family 30 A8 zinc transporter (SLC30A8) have been consistently associated with diabetes. Women with gestational diabetes are at moderate risk of developing diabetes type 1 and 2 after pregnancy, in addition to complications to the fetus. We investigated the association of the polymorphisms rs7799039 (LEP) and rs13266634 (SLC30A8) in a case-control study in Euro-Brazilians with gestational diabetes (GDM, N = 180). Realtime PCR with fluorescent probes (TaqMan system) was applied to genotyping. All polymorphisms were in Hardy-Weinberg equilibrium. The minor allele frequencies, for healthy and GDM, respectively, for the A-allele (LEP gene rs7799039) were 40.3% (95%CI = 35-45%) vs 36.6% (95%CI = 31-42%), P = 0.345; and for the T-allele (SLC30A8 gene rs13266634) were 27.8% (95%CI = 23-32%) vs 23.5% (95%CI = 18-29%), P = 0.227. Genotype comparisons for both polymorphisms showed no significant difference (P > 0.05). The polymorphisms rs7799039 and rs13266634 were not associated with GDM in the population studied (P > 0.05). The minor allele frequencies for both polymorphisms were similar to those of other Caucasian populations.