Background/ Objectives: To evaluate the association between the carbohydrate quality (CQI) and weight change or incident overweight/obesity (BMI¿25 kg/m2) in the ¿Seguimiento Universidad de Navarra (SUN)¿ cohort. Subjects/ Methods: 8 741 participants initially free of overweight/obesity were followed¿up for a median of 7.9 years. We evaluated at baseline the CQI following 4 criteria: dietary fibre intake, glycemic index (GI), whole grains/total grains ratio and solid carbohydrates/total carbohydrates ratio. Subjects were classified into quintiles according to CQI. Weight was recorded at baseline and updated every 2 years during follow¿up. Results: Increasing CQI of diet was not significantly associated with lower weight gain, although participants in the highest quintile had the lowest average crude weight gain (+211 g/year). We observed 1 862 incident cases of overweight/obesity during followup. CQI was significantly associated (p for trend 0.006) with lower risk of overweight/obesity: adjusted OR for the 4rd and 5th quintiles: 0.81 (95% CI 0.66 to 0.99), and 0.74 (95% CI 0.60 to 0.92), respectively. Conclusions: In this Mediterranean cohort, CQI showed a significant inverse association with the incidence of overweight/obesity, which highlights that carbohydrate intake guidelines related to obesity prevention should be focused in improving the CQI of the diet.