In this study, the effect of the context-based approach on pre-service primary school teachers' understanding of matter and its states and their attitude towards chemistry was investigated. Using a simple experimental design, the study was conducted with 35 pre-service primary school teachers who were exposed to context-based material with storylines. Two instruments were used to collect data as pre-test, post-test, and delayed-test: the "States of Matter Achievement Test (SMAT) and the Chemistry Attitude Scale (CAS)." Also, semi-structured interviews were conducted with the pre-service primary school teachers after the implementation. The results indicated that the use of storylines embedded within a context-based approach resulted in better understanding of the concepts of matter and its states. Furthermore, the approach helped pre-service teachers gain positive attitudes towards chemistry. This improved performance was also observed in the delayed test. Overall, the results showed that the intervention had considerable effects on remedying pre-service teachers' alternative conceptions. Some suggestions are made on the implications for practice and learning.