Investment decisions are critical for corporations, which have to create value for their shareholders. Large corporations have stocks traded in the stock market and, if they deliver return on capital below expectations, shareholders will sell the stocks in their hands, in order to invest in other companies, and problem of loosing value will be even worse. Therefore, the cost of capital is central to Corporate Finance. It strongly impacts investment and divestment decisions, measures of profitability, and performance evaluation. Continuing previous academic studies about corporations in the U.S. and Argentina, the objective of this research is to know the practices in estimating the cost of capital in Brazil. Besides the relevance of the Cost of Capital as a subject, by publishing the results of this research and the resulting dissertation, we intend to provide the academic and corporate communities with a practical and ready-to-use tool.