The purpose of this study was to determine if any differences exist in inquiry skills between science students using the Intermediate Science Curriculum Study (ISCS) materials and those using a more traditional approach. The Tab Science Test was administered to seventh-, eighth-, and ninth-grade science students in both ISCS and non-ISCS groups. Each grade level was treated as a separate experiment. The test scores were subjected to analysis of covariance with IQ scores used as a blocking factor and the student's father's educational level as the covariate. No differences were found between the two groups in the seventh or eighth grade. A difference in favor of the non-ISCS group was found in the ninth grade. Differences in the clue question (in the Tab Test) selection were also investigated. This difference was noted only in the ninth grade, with the ISCS students exhibiting fewer inefficient patterns of inquiry and more efficient patterns than the non-ISCS group. The ISCS program as used by the teachers involved did not produce clear gains in inquiry skills of students as measured by the Tab Test. However, the Tab Test reliability was low. Caution should be taken in interpreting results. (Author/EB)