Introduction: Early intervention conceived as a program for young infants and toddlers with developmental needs and their families, how early intervention practice establishes family participation in the service process - from referral, evaluation, Individualized Family Service Plan (IFSP) meeting, to service delivery - was considered in this article. Employing disability studies perspectives, the study contends that although families have gained legal rights for family participation in the law, the requirements do not guarantee the quality of family participation. Using a qualitative case study approach, this study looked at both participation and perceptions of families in the early intervention service process in the metropolitan area of the US. Case description: Three families’ experience in the process of early intervention was observed, and how these parents reflect on their participation in the development of early intervention service planning and delivery was examined through in-depth interviews. Discussion and evaluation: Findings showed that the families’ participation varied by service providers. The disparity resulted from variable availability, competency levels, and approaches of individual service providers during the service process. In addition, early intervention professionals who are bounded by the requirements in a professional bureaucracy, including the procedural requirements, often impinge on the quality of family participation and limit families’ opportunities for quality service provision. Conclusions: The paper suggests rethinking about how the practice can be implemented.