OBJECTIVE: To assess the relationship between plasma leptin concentration during third trimester of pregnancy and blood pressure, independent of body mass index at examination and other potential confounders. STUDY DESIGN: A cross-sectional study was performed including 95 women (61 non-diabetic women, 34 women with gestational diabetes (GD)) in their third trimester of pregnancy. The relationship between plasma leptin and blood pressure was investigated using multiple linear regression analysis. RESULTS: Independent of body mass index (BMI), leptin was positively correlated to systolic (P = 0.024) and diastolic blood pressure (P = 0.002). Stepwise linear regression identified leptin as the only variable independently associated with systolic blood pressure (P = 0.003), while leptin (P <0.001) and age (P = 0.024) were the only variables independently correlated to diastolic blood pressure. CONCLUSIONS: This study reports for the first time that, independent of BMI at examination, presence of GD or other confounders, plasma leptin is positively correlated with blood pressure in pregnant women.