The objectives of this study were to better describe adult day service (ADS) programs and determine how various structural and case mix characteristics of ADS were empirically associated with the services provided in and the social environments of adult day programs. All directors of ADS programs in Minnesota (United States) were contacted from 2011 to 2012 to complete a detailed online survey that collected information on ADS structure, client case mix, services and activities, and social environment (n = 83; 67.5% response rate). Several structural characteristics and case mix indicators (e.g., number of clients attending) were significantly associated (p < .05) with specific types of ADS service provision, such as health monitoring. Programs that were adequately staffed and perceived as pleasant appeared to also have a more vibrant social environment. The results suggest the potential need for bolstering staffing and enhancing the physical environment of ADS programs.