BACKGROUND:Ultraprocessed food consumption has increased in the past decade. Evidence suggests a positive association between ultraprocessed food consumption and the incidence of overweight and obesity. However, few prospective studies to our knowledge have investigated this potential relation in adults. OBJECTIVE:We evaluated the association between ultraprocessed food consumption and the risk of overweight and obesity in a prospective Spanish cohort, the SUN (University of Navarra Follow-Up) study. DESIGN:We included 8451 middle-aged Spanish university graduates who were initially not overweight or obese and followed up for a median of 8.9 y. The consumption of ultraprocessed foods (defined as food and drink products ready to eat, drink, or heat and made predominantly or entirely from processed items extracted or refined from whole foods or synthesized in the laboratory) was assessed with the use of a validated semiquantitative 136-item food-frequency questionnaire. Cox proportional hazards models were used to estimate adjusted HRs and 95% CIs for incident overweight and obesity. RESULTS:A total of 1939 incident cases of overweight and obesity were identified during follow-up. After adjustment for potential confounders, participants in the highest quartile of ultraprocessed food consumption were at a higher risk of developing overweight or obesity (adjusted HR: 1.26; 95% CI: 1.10, 1.45; P-trend = 0.001) than those in the lowest quartile of consumption. CONCLUSIONS:Ultraprocessed food consumption was associated with a higher risk of overweight and obesity in a prospective cohort of Spanish middle-aged adult university graduates. Further longitudinal studies are needed to confirm our results. This trial was registered at clinicaltrials.gov as NCT02669602.