BACKGROUND: Policies call on afterschool programs to improve the physical activity and nutrition habits of youth attending. No tool exists to assess the extent to which the afterschool program environment meets physical activity and nutrition policies. PURPOSE: To describe the development of the Healthy Afterschool Activity and Nutrition Documentation (HAAND) instrument, which consists of two subscales: Healthy Afterschool Program Index for Physical Activity (HAPI-PA) and the HAPI-Nutrition (HAPI-N). METHODS: Thirty-nine afterschool programs took part in the HAAND evaluation during fall/spring 2010-2011. Inter-rater reliability data were collected at 20 afterschool programs during a single site visit via direct observation, personal interview, and written document review. Validity of the HAPI-PA was established by comparing HAPI-PA scores to pedometer steps collected in a subsample of 934 children attending 25 of the afterschool programs. Validity of the HAPI-N scores was compared against the mean number of times/week that fruits and vegetables (FV) and whole grains were served in the program. RESULTS: Data were analyzed in June/July 2011. Inter-rater percent agreement was 85%-100% across all items. Increased pedometer steps were associated with the presence of a written policy related to physical activity, amount/quality of staff training, use of a physical activity curriculum, and offering activities that appeal to both genders. Higher servings of FV and whole grains per week were associated with the presence of a written policy regarding the nutritional quality of snacks. CONCLUSIONS: The HAAND instrument is a reliable and valid measurement tool that can be used to assess the physical activity and nutritional environment of afterschool programs.