Cost of equity valuation in emerging markets is a relevant task for many groups: international investors, local investors, business administrators and regulators. Therefore, this dissertation has four main objectives: (i) to discuss critically the theoretical aspects of the cost of equity valuation models that have been proposed to emerging markets; (ii) to discuss the mainstream methodologies applied in the cost of equity valuation models for the parameters estimation; (iii) to implement the CAPM and D-CAPM cost of equity valuation models in Argentinean, Brazilian, Chilean and Mexican companies with the aim to make various kinds of comparative analysis and to evaluate the impact of the model choice upon investors decisions; and (iv) to evaluate the explanatory power of the risk measures against future returns. The results indicate that: (i) the choice of the cost of equity valuation model has a relevant impact upon investors decisions regarding asset allocation; (ii) the downside risk measures (downside betas) had a better explanatory power against future returns for Argentinean, Brazilian and Mexican companies and also have been more useful in portfolio construction. Nevertheless, there was no single risk measure that performed better simultaneously in all the markets being analyzed.