According to many documents, there is a strong need to renew science education. One way could be to work with SSI (socio-scientific issues). This paper reports on both students' and teachers' experiences and learning when working with socio-scientific issues in science education in secondary school (aged from 13 to 16). The approach is multidimensional, as factors that influence cognition as well as motivation and the forming of attitudes are complex. Results suggest that SSI work forms are more important than personal factors for explaining outcomes. Relevant issues, autonomy and functioning group work seem to be important aspects of successful SSI work together with structure provided by the teacher, and information that challenges previous knowledge. In general, SSI seems to be most efficient for students, who believe that they learn from presenting and discussing their knowledge, focus on "the large picture", acknowledge own responsibility for learning, find school science personally relevant and are self-efficacious. It seems that the outcomes from SSI work are much in the hands of the teacher. This paper is a short summary of the first year and quantitative part of the project. Further results from the project will later be found in our homepage (http://www.sisc.se).