The purpose of this study was to investigate theeffectiveness of iconic-based rhythmic instruction on middle school instrumentalists' ability to read rhythms at sight inthe preparation of music for sight-reading. One hundred thirty-onemiddle school students from 12 randomly assigned bands in theMidwestern United States provided data for a pretest-posttestcontrol-group design.Results from an analysis of covariance revealed thatno group obtained a significant difference on the posttestmean scores from the rhythmic performance test after a nine-weekperiod. Because results from individual schools showed considerablevariation, other variables were observed to see if they weresignificant. It was indicated that a significant interaction between theindividual school and the pretest to posttest measurement exists. Inlight of these findings, it is speculated that the key to improvinga student's rhythm-reading ability may be dependent not only onthe method, but also on the quality of instructional delivery.