The purpose is to examine validity and reliability for an obesity risk assessment tool developed in Spanish for immigrant families with children, 3–5 years old using an 8-week cross-sectional design with data collected over 1 year at Head Start and Special Supplemental Nutrition Program for Women, Infants and Children [WIC]. Parent/child dyads (206) provided a child obesity risk assessment, three child modified 24 h dietary recalls, three child 36+ h activity logs and one parent food behavior checklist. Main outcome measures were convergent validity with nutrients, cup equivalents, and diet quality and three assessments of reliability that included item difficulty index, item discrimination index, and coefficient of variation. Validity was demonstrated for assessment tool, namedNiños Sanos. Scales were significantly related to variables in direction hypothesized [p≤ 0.05]: Healthy Eating Index, fruit/vegetable cup equivalents, folate, dairy cup equivalents, vitamins D, β-carotene, fiber, saturated fat, sugar, time at screen/ sleep/physical activity and parent behaviors. Three measures of reliability were acceptable. The addition of nutrient values as an analytical validation approach adds strength and consistency to previously reportedNiños Sanosvalidation results using children’s blood biomarkers and body mass index. This tool can be used by health professionals as an assessment of obesity risk in several capacities: (1) screener for counseling in a clinic, (2) large survey, (3) guide for participant goal setting and tailoring interventions, and (4) evaluation.