The study explores teachers' experiences of teaching a context-based chemistry course, "Salters Advanced Chemistry", as compared with teachers of a conventional course. Second, main factors that appear to influence decisions over whether or not to adopt context-based courses are investigated. Two hundred and twenty-two teachers' views of a context-based and a conventional school advanced chemistry course were obtained from a questionnaire. Responses were analysed in six dimensions: motivation, chemical knowledge and development of concepts, learning activities, assessment, challenge to teachers and students, and teacher support. Both sets of teachers agreed that the context-based course is more motivating to study and teach, that students would be more interested in chemistry and more likely to go to university to study chemistry, that students would be better able to study independently but that it is more demanding to teach and study. The groups differed principally about concept development and teaching strategy. The context-based teachers believed that their course gave as good a foundation for further study as a traditional course and that the spiral curriculum was advantageous. Conventional course teachers disagreed with both statements. One significant implication to emerge from the study is the crucial role played by in-service support in influencing the impact of a curriculum innovation.