Initially funded in 1988, the CATCH (Coordinated Approach To Child Health) program is a school-based health promotion and childhood obesity prevention program. It was designed to improve physical activity (PA) and healthy food choices in school-aged children. The program has since expanded to include the CATCH Early Childhood (CEC) program, developed for preschool-aged children (ages 3-5 years). The CEC program incorporates preschool-based enhanced PA, nutrition, family educational components, and staff learning materials in a health promotion program aimed at young children. The program is one of the few interventions that includes nutrition, PA, and family/staff components targeting young children (e.g. < 5 years). This thesis evaluated the impact of CEC programming on young children’s nutrition behaviours, food knowledge, and PA levels before and after implementation of the CEC program. Registered Early Childhood Educators (RECEs) were trained and implemented the program for 6-months. Our results demonstrated some significant findings relevant to preschooler program development, but do not directly support the implementation of the CEC program specifically. This study adds to the current body of literature around early intervention programs within daycare settings, but further research is needed to quantify whether all components of the CEC program can positively impact health outcomes (e.g. nutritional choices and PA behaviours) among this cohort.