In this article, the predictive strength of the Junior Secondary Certificate (JSC) examinations in integrated science in predicting the performance of students in the Senior Secondary Certificate (SSC) examinations in chemistry in Zaria metropolis, Nigeria was examined. The study employed the ex-post facto design. The study population comprised of four hundred students from four purposefully selected secondary schools in Zaria metropolis. Out of this population, a sample of two hundred students was selected through the stratified random sampling technique. Data were collected through an inventory and analysed with the use of z-test and correlation analysis. The results of the investigation revealed that the academic achievement of students in integrated science in the Junior Secondary School Certificate (JSC) examinations among the selected Secondary schools in Zaria metropolis was a poor predictor of later achievement in chemistry at Senior Secondary School Certificate (SCE) examination. It is recommended that more qualified and competent teachers should be trained and employed to teach Integrated Science in Junior Secondary School and classroom teachers should try as much as possible to relate the concept of integrated Science to chemistry and other basic sciences.
