The purpose of this study was to compare the academic achievement of students in looping programs from school systems in East Tennessee to their peers in traditional one-year instructional programs. Looping is defined as any program design that perpetuates a cohesive student group with the same teacher for more than one year. The study included all students who had completed fourth grade in 2001 at every school in East Tennessee that implemented a third/fourth grade looping design. Student scores reported for 1999, 2000, and 2001 on the TerraNova Standardized Achievement Test were obtained from individual student records. Comparisons were made on the Total Reading, Total Language, Total Math, and Total Battery scores. Differences between program design groups (looping and traditional) on "pre-looping" second grade (1999) scores were assessed using t-tests for two independent groups. Two-way Analysis of Covariance (ANCOVA), was used to examine the main effects of program design and student gender on 2000 and 2001 test scores, along with program design x gender interactions, while controlling for prior test score differences. The findings suggested that students in looping classrooms benefited academically by remaining with the same teacher and classmates for two successive years. Significant main effects were detected for program design in first year comparisons, as indicated by significantly higher scores on all four subtests. Scores for those in the looping classrooms remained significantly higher in second year comparisons on each subtest, except Total Language, even after controlling for third grade (2000) test scores. Significant main effects for gender were detected after the first year of participation in each design. This included significantly higher Total Language and Total Battery scores for female participants. No significant differences by gender were detected when scores were compared on the four subtests at the end of the two-year cycle. A program design x gender interaction was detected at the end of the first year. This interaction showed that female participants in looping classrooms showed higher Total Math achievement. A program design x gender interaction also occurred after the second year where male participants in the looping classrooms obtained higher Total Language scores.