This study investigated the effectiveness of reading intervention on at-risk readers from first through third grade. The 34 children below the 20th percentile on an oral reading fluency test participated in the reading intervention program for 15 weeks. They received small group instruction in one 40-minute session per week. Data were analyzed with one-way ANOVA, paired t-test and effect size for individual cases. Upon completion of the intervention, at-risk first graders showed significantly higher performance in print concept, word recognition, oral reading fluency and reading comprehension. The at-risk second and third graders improved only in oral reading fluency. Most of children who received the intervention demonstrated a large effect in oral reading fluency.