This book refers to the knowledge of financial indicators and the influence on decision making, measuring the level of knowledge of individual microentrepreneurs about the financial indicators of their business. From this theme, we had as a general objective to present the importance of indicators for the financial management of organizations and contributions of these data as a guide in the decision-making process. As specific objectives: emphasize the importance of financial indicators for decision making, present the MEI universe and investigate the financial knowledge of microentrepreneurs in Garanhuns. About the understanding of these indicators: 75% have knowledge, 88% say they have control and mastery of their fixed and variable costs, however, only 50% analyze the net and operating income, which contradicts itself in terms of understanding and use of these parameters, and that in fact affirm the relevance of knowing the data that are interdependent in their structure, knowing their fixed and variable costs, contribution margin, break-even point and net and operating income, serve as a guide to possible adversities.