Curriculum integration has recently stirred growing interest in educational discourses. New Finnish core curricula for basic education and for general upper secondary schools encourage and even obligate schools to integrate the curriculum. Integration has been deemed to be important, as the boundaries between school subjects have remained unnecessarily rigid. Integration is needed to construct a coherent structure for educational knowledge allowing for the study of broad-ranging topics crossing the subject boundaries. This paper is a piece of quantitative research based on a questionnaire completed by Finnish student teachers (N = 243) studying to teach a range of subjects in secondary schools (age groups 13-18). The questionnaire explored student teachers' readiness to generate integrative topics between subjects. Variables such as teaching experience or expertise in several subjects did not correlate with the readiness and the subject matter was found to be the main correlating variable. The results outlined in this paper indicate that subject specific differences exist in the potentiality of subjects to be integrated.