This article is a study on self-employment in Spain, and particularly on a target group: worker-members of small limited liability companies. Through the descriptive analysis of a sample of workers extracted from the Continuous Work History Sample (CWHS), on the one hand, we evaluate the conditions which determine the decision to become your own employer, and on the other hand, we reflect a number of sociodemographic characteristics related to the working life of our target group. The most relevant result demonstrates that worker-members of small and medium-sized enterprises (SMEs) can be differentiated as an independent group with its own features, despite the economic literature has usually studied them within the selfemployed workers' collective. This group represents about a quarter of the totality of the Spanish selfemployed work, thus becoming a very important part of the national economy in the wealth and employment creation.