The purpose of this study was to test the reliability and validity of the Checklist for Function-Focused Care in Service Plans. Function-focused care is a care approach that optimizes function and physical activity during all care interactions. This study used baseline data from the first cohort of the study titled Dissemination and Implementation of Function-Focused Care for Assisted Living Using the Evidence Integration Triangle (FFC-AL-EIT). A total of 242 participants were recruited from 26 assisted living facilities. The majority of participants were White, female, and unmarried. There was support for internal consistency with an alpha coefficient of .96, interrater reliability with a correlation of .80, construct validity based on Rasch analysis and INFIT statistics ranging from 0.69 to 1.29, and a significant association with function-focused care activities. Although there is some support for reliability and validity of the measure, modifications are recommended to add more challenging items.