This study examined the effects of the Waterford Early Reading Program on reading achievement gains across the first-grade year. The results of this longitudinal analysis demonstrated meaningfully greater gains on reading achievement for those with access to the Integrated learning system (ILS) (n[superscript 2] =.10). Furthermore, the positive effects associated with access to the ILS were greatest for students demonstrating the lowest initial reading skills--those with reading skills at or below the 25th percentile at the beginning of first grade (n[superscript 2] =.43). The results are interpreted as support for the ILS in early reading instruction, provided that the ILS is fully integrated into the teachers' reading curriculum and is not used as a stand-alone program.