Objective: Determine validity of Day in the Life Questionnaire-Colorado (DILQ-CO) as a dietary assessment tool for classroom-administered use. Methods: Agreement between DILQ-CO responses and weighed plate waste measured in 125 fourth-grade students in 2 low-income schools. Validity assessed by comparing reported school lunch items and portion size estimations on DILQ-CO to plate waste. Agreement calculated using Spearman correlations, kappa statistic, percent agreement, exclusions, intrusions, and mismatches. Results: Substantial-to-almost-perfect agreements for students' reports of food eaten in all but the dessert category (kappa coefficients: 0.65-0.97; 81%-99% matches). Significant correlations (P less than or equal to 0.05) were found between students' reports of how much was eaten and plate waste measurements for 6 of 10 items; agreement ranged from 47%-82%. Conclusions and Implications: Classroom-administered DILQ-CO provided a valid measure of reported school lunch items, with amounts reported eaten of lower but still acceptable agreement. This tool shows promise as a group-administered dietary recall with children. (Contains 2 tables.)