Background: During 2012, Massachusetts adopted comprehensive school competitive food and beverage standards that closely align with Institute of Medicine recommendations and Smart Snacks in School national standards. Objective: We examined the extent to which a sample of Massachusetts middle schools and high schools sold foods and beverages that were compliant with the state competitive food and beverage standards after the first year of implementation, and complied with four additional aspects of the regulations. Design: Observational cohort study with data collected before implementation (Spring 2012) and 1 year after implementation (Spring 2013). Participants/setting: School districts (N=37) with at least one middle school and one high school participated. Main outcome measures: Percent of competitive foods and beverages that were compliant with Massachusetts standards and compliance with four additional aspects of the regulations. Data were collected via school site visits and a foodservice director questionnaire. Statistical analyses performed: Multilevel models were used to examine change in food and beverage compliance over time. Results: More products were available in high schools than middle schools at both time points. The number of competitive beverages and several categories of competitive food products sold in the sample of Massachusetts schools decreased following the implementation of the standards. Multilevel models demonstrated a 47-percentage-point increase in food and 46-percentage-point increase in beverage compliance in Massachusetts schools from 2012 to 2013. Overall, total compliance was higher for beverages than foods. Conclusions: This study of a group of Massachusetts schools demonstrated the feasibility of schools making substantial changes in response to requirements for healthier competitive foods, even in the first year of implementation.