This paper describes the main features of mutual funds and ETF s, developing a work aimed at combining these financial instruments, to take benefit from its joint advantages and propose an attractive investment alternative in the stock market. By applying modern portfolio theory to this particular case, some ETF s are selected to create eight hypothetical portfolios, each one with a particular objective and addressed to different investor profiles. The document also contains the framework used to address the problem, the treatment given to it and the obtained results, which are analyzed from the performance achieved by each portfolio, comparing them with each other and with the market performance between January 2010 and June 2013.