This research aims to contribute to the understanding of factors related to the decision of micro-entrepreneurs on whether to formalize their operations, or to keep them informal. Although there are studies on the entrepreneurial profile, there are few works that discuss the reasons or conditions that lead to the formalization of a microenterprise. A descriptive and quantitative survey was therefore conducted with 65 entrepreneurs: 40 formal company owners and the other 25 informal, all located in the municipality of Diadema (SP). The participants received a questionnaire with questions related to demographic aspects and other questions aimed at identifying their perceptions of formality and informality in their businesses. The main results show that (1) some of the socioeconomic characteristics of the micro-entrepreneurs demonstrate potential or actual correlation with the decision on whether to formalize or remain informal; (2) we also noted the existence of a relationship between business variables and the option to formalize the business; and (3) we found discrepancies in relation to the presence of information and the concept of informality in businesses when comparing formal and informal microenterprises.