In the United States, the Social Security Administration (SSA) provides financial benefits through Supplemental Security Income (SSI) to many individuals with intellectual and developmental disabilities (IDD). Family members and service coordinators (SCs) provide a critical role in applying for SSI on behalf of individuals with IDD. The present study uses a street-level lens to understand the implementation of SSI policy from the perspective of family respondents and SCs based upon their experiences with the application process. Using surveys developed from focus groups and interviews with family members and SCs, the study explores parts of the application process that facilitated success and barriers that hindered the procurement of benefits, and also elicited suggestions for improvement of the process. Survey respondents included 122 family members and 122 SCs in the western region of New York State. Findings reflect experiences at the various steps of the application process including initial applications, interviews and assessments, as well as experiences with SSA workers. Despite several significant differences, a general congruence between family respondents and SCs suggests considerable opportunities for improvement. This study provides a preliminary evaluation of a complex process from two different perspectives, with implications for policy, practice and future research.