In this study we investigate the factors that shape the attitudes of scientists toward starting their own business or working in a private sector firm. The analysis is based on data collected from scientists working in the German Max Planck Society, a research institution devoted to basic science. We find that the scientists’ evaluations of the attractiveness of working in a private sector firm or of starting their own business differ considerably according to their academic discipline and the perceived commercial potential of their research. The ability to take risks, prior work experience in private firms, and personal experience with industry cooperation lead to a positive attitude towards switching to private sector employment or entrepreneurship. Strong willingness to freely distribute research findings are related to a low appeal of private sector work.