This work focuses on the main variables that explain the prices of the voice services established by mobile service providers in Colombia. This will be done by analyzing different variables that characterize this sector, like, historical prices stablished by all operators, all the investments made in network development, market sharing and all the existing regulatory measures. We develop a model for data panels in the period between 2005 and 2011, which makes evident the existing interdependence amongst the different companies when setting rates. It is also evident the leadership of one of the competitors and the existing price war between providers.