Background: Interest is assumed to be relevant for students' learning processes. Many studies have investigated students' interest in science; most of them however have not offered differentiated insights into the structure and elements of this interest. Purpose: The aim of this study is to obtain a precise image of secondary school students' interest for school and out-of-school learning opportunities, both formal and informal. The study is part of a larger project on measuring the students' Individual Concept about the Natural Sciences (ICoN), including self-efficacy, beliefs and achievements next to interest variables. Sample: Next to regular school students, a specific cohort will be analyzed as well: participants of science competitions who are regarded as having high interest, and perhaps different interest profiles than regular students. In the study described here, participants of the International Junior Science Olympiad (N = 133) and regular students from secondary schools (N = 305), age cohorts 10 to 17?years, participated. Design and Methods: We adapted Holland's well-established RIASEC-framework to analyze if and how it can also be used to assess students' interest within science and in-school and out-of-school (leisure-time and enrichment) activities. The resulting questionnaire was piloted according to quality criteria and applied to analyze profiles of different groups (boys-girls, contest participants-non-participants). Results: The RIASEC-adaption to investigate profiles within science works apparently well for school and leisure-time activities. Concerning the interest in fostering measures, different emphases seem to appear. More research in this field needs to be done to adjust measures better to students' interests and other pre-conditions in the future. Contrasting different groups like gender and participation in a junior science contest uncovered specific interest profiles. Conclusions: The instrument seems to offer a promising approach to identify different interest profiles for different environments and groups of students. Based on the results, further studies will be carried out to form a solid foundation for the design of enrichment measures.