We present the Transit Monitoring in the South (TraMoS) project. TraMoS has monitored transits of 30 exoplanets with telescopes located in Chile since 2008, whit the following goals: (1) to refine the physical and/or orbital parameters of those exoplanet system, and (2) to search for variations in the mid-times of the transits and in other parameters such as orbital inclination or transit's depth, that could indicate the presence of additional bodies in the system. We highlight here the first results of TraMoS in three selected exoplanets.