This study investigates the association between ultraprocessed food (UPF) consumption and cardiometabolic risk factors in preschool children aged 3-6 years. The analysis is based on data from the Childhood Obesity Risk Assessment Longitudinal Study (CORALS), which recruited participants from 7 cities in Spain between March 22, 2019, and June 30, 2022. A total of 1426 children were included, with mean age of 5.8 years (SD 1.1 years). Energy-adjusted UPF consumption was measured using food frequency questionnaires and categorized into tertiles. Adiposity and cardiometabolic parameters were assessed using standardized methods. The results show that higher UPF consumption was positively associated with higher z-scores for body mass index (BMI), waist circumference, fat mass index, and fasting plasma glucose, while it was inversely associated with high-density lipoprotein (HDL) cholesterol. Children in the highest tertile of UPF consumption had higher BMI z-scores, waist-to-height ratio, fat mass index, systolic blood pressure, and a higher prevalence of overweight or obesity. Mothers of these children were younger, had higher BMI, were more likely to be overweight or obese, and had lower education levels and employment rates. Substituting 100 g of UPFs with 100 g of unprocessed or minimally processed foods was associated with lower z-scores for BMI, fat mass index, and fasting plasma glucose. The study highlights the need for public health initiatives to promote the replacement of UPFs with unprocessed or minimally processed foods to reduce cardiometabolic risk factors in children.This study investigates the association between ultraprocessed food (UPF) consumption and cardiometabolic risk factors in preschool children aged 3-6 years. The analysis is based on data from the Childhood Obesity Risk Assessment Longitudinal Study (CORALS), which recruited participants from 7 cities in Spain between March 22, 2019, and June 30, 2022. A total of 1426 children were included, with mean age of 5.8 years (SD 1.1 years). Energy-adjusted UPF consumption was measured using food frequency questionnaires and categorized into tertiles. Adiposity and cardiometabolic parameters were assessed using standardized methods. The results show that higher UPF consumption was positively associated with higher z-scores for body mass index (BMI), waist circumference, fat mass index, and fasting plasma glucose, while it was inversely associated with high-density lipoprotein (HDL) cholesterol. Children in the highest tertile of UPF consumption had higher BMI z-scores, waist-to-height ratio, fat mass index, systolic blood pressure, and a higher prevalence of overweight or obesity. Mothers of these children were younger, had higher BMI, were more likely to be overweight or obese, and had lower education levels and employment rates. Substituting 100 g of UPFs with 100 g of unprocessed or minimally processed foods was associated with lower z-scores for BMI, fat mass index, and fasting plasma glucose. The study highlights the need for public health initiatives to promote the replacement of UPFs with unprocessed or minimally processed foods to reduce cardiometabolic risk factors in children.