Teachers' career choice motives are defined as the interests, orientations, and motives of young people that motivate them to aspire the teaching career. Teachers' career choice motives have been shown to impact teaching and job retention. Many studies investigated teachers generic career choice motives but studies on teachers' subject-specific career choice motives are widely missing. This study investigated preservice biology teachers' (N = 168) generic and subject-specific career choice motives by using open-ended questions and applying a qualitative content analysis approach to the data analysis. Category systems with generic and subject-specific career choice motives were deductively developed and inductively refined. The findings suggest intrinsic and altruistic motives to be most prominent. In contrast to most previous studies, the extrinsic motive benefits and returns of the teaching profession was also mentioned quite often. Furthermore, the qualitative approach made it possible to differentiate between the motives subject interest in biology and relevance of biology. Only small relationships were found between the generic and the subject-specific career choice motives of the participants and between the career choice motives and sociodemographic background variables. Implications for future research and teacher education are proposed.