This article uses data from an ethnographic study that examined the delivery of home-based services in early intervention. Participants were families with an infant or toddler with special needs, and professionals providing early intervention services to these and other families. The study examined an early intervention program that uses primarily a transdisciplinary approach to home-based service delivery. Perspectives on the delivery of services were elicited by ethnographic interviewing, participant observation of home visits, and the review of program structure, artifacts, and documents to determine what makes this program effective in the delivery of services. The data revealed that effectiveness of service delivery is dependent upon professionals creating a cultural environment that is similar in all homes during home visits. The discussion addresses the difficulty in defining and then implementing a family-centered service delivery model that takes individual differences into account. (Contains 2 tables and 1 figure.)