This study explored the effects of "Reading Mastery Plus" in grades K-2 at a Title 1 school with six students with intellectual and developmental disabilities (IDD). Two students in each of grades kindergarten, 1, and 2 participated. "Diagnostic Indicators of Basic Early Literacy Skills (DIBELS)" spring fluency probes were used to assess changes in students' beginning reading skills and risk status. Results indicated students made large overall gains on fluency measures. Additionally, there were several improvements in the "DIBELS" risk status categories. The implications for future research are discussed. (Contains 5 tables.)