This article presents a comparison between the professional and curricular conceptions of two samples of secondary education science teachers in Spain, who differed in their years of teaching experience and in whether or not they had participated in a long-duration scientific-pedagogical refresher course. Using the data from their responses to a questionnaire, aspects of their professionalism as teachers (motivation and work satisfaction) and aspects of the curriculum related to content, teaching methods and evaluation were analyzed. The results show a broader professionalism and a higher level of satisfaction in the case of the teachers with more experience and a higher level of professional training. The study found significant differences in whether the pupils' ideas were regarded as erroneous, and in whether laboratory practical work was used to test theory. It concludes by setting out a series of reflections with the aim of working towards improving teachers' "professional development."