Our interest is entrepreneurship and marketing and their possible overlap and/or synergy. This chapter is about the role marketing plays in various business start-ups. It makes a distinction between rational and natural business start-ups. To understand this distinction, the chapter starts by outlining a recent development of the subject of entrepreneurship as we see it, that it is possible to talk about a narrow and a broad view of the field of entrepreneurship today. The chapter ends by discussing which role marketing can play in different business start-ups in general and in rational and natural business start-ups in particular.