Science curriculum reform, the act of restructuring science curriculum, is advocated by major educational stakeholders in the nation for improving student science achievement and attitudes toward science. An approach for restructuring science curricula is to include science intervention programs in established curricula. For this study, the effectiveness of a science intervention program on science achievement and attitudes of middle-grade students attending a 5-week academic enrichment program was determined. Effective curricular components, as identified by relevant research studies, were incorporated in the intervention program. Those components included appropriate content, as designated by national standards and state-mandated instructional objectives for Georgia, and the learning cycle teaching procedure. A mixed-methodology research design was used. For the quantitative data, a criterion-referenced test and a survey measuring attitudes toward science were administered to the students at the beginning and end of the program. Correlational t-tests were conducted using pretest and posttest scores from the criterion-referenced test and pretest and posttest attitude survey scores. Students' science achievement (p < .001) and attitudes toward science (p < .05) were higher following participation in the science intervention program. Qualitative data, which included narrative descriptions of students' behaviors as recorded in a teacher-researcher daily log, supported the findings of the quantitative research. Results from the study provide implications for science curriculum reform.