The purpose of this study was to investigate second-grade students' ("N" = 128) rhythm-reading achievement and retention after 5 or 10 min of weekly instruction for 3 weeks. Eight intact classes were placed into two groups. Group 1 received 5 min of rhythm-reading instruction during weekly music class, whereas Group 2 received 10 min of rhythm-reading instruction during weekly music class. Treatment lasted 3 weeks, after which students individually completed posttest I. After 2 weeks of no rhythm-reading instruction or practice, students were individually administered posttest II to measure retention. Results indicated that both groups successfully read rhythms after instruction and retained rhythm-reading skills after two additional weeks of no instruction. Between-group analysis suggested that 5 min of instructional time is equally as effective as 10 min on student achievement and retention. Implications include increased efficiency in planning and teaching, increased student engagement, and effective instructional practices in the elementary music classroom.