This study aims to analyze the financial management of small companies originated by necessity and opportunity. The literature review adresses the different types of entrepreneurs, the definition of small companies and characteristics the financial management of small companies. The field research was conducted with small companies, located in Rio de Janeiro. It was found that the entrepreneurs showed no significant differences in relation to their management approach on the studied items. Nevertheless some findings are important to highlight, such as the fact that the entrepreneur by opportunity presented a higher level of education, that the Income Statement is the accounting report most used by both types entrepreneurs and that the Microsoft Excel is the main financial control tool.