This paper studies how heterogeneous individuals, that differ by entrepreneurial skills and productivity as a worker, endogenously choose their occupation (workers vs. entrepreneurs) based on expected income comparison (wages vs. profits). Each entrepreneur runs a firm that produces a single variety of a horizontally differentiated good under monopolistic competition. We show that the cutoff for occupational selection between workers and entrepreneurs is a negatively sloped curve in the space of individual characteristics. The form of this cutoff curve does not depend on the distribution of individual characteristics, but is affected by the elasticity of substitution between varieties. Changes in the distribution of individual characteristics can shift the cutoff curve. Thus individual employment choices depend not only on the distribution of characteristics, but also on the degree of competition in the market. We show that when the distributions of entrepreneurial skills and worker productivity are independent and follow power laws, an increase in the average worker’s ability decreases the share of entrepreneurs, whereas changes in the average entrepreneur’s skills do not affect this share. Estimates based on Current Population Survey (CPS) data are in line with the theoretical shape of the cutoff curve, and our estimates of the elasticity of substitution are close to those usually found in the literature.