Geophysical methods as resistivity, refraction seismic, magnetics, gravity and thermometry have been applied successfully to paleovalleys investigations. This paper deals with the application of geophysical methods to the investigation of paleovalleys which contain cassiterite in the Garças river, in granitic area situated 70 km West of Porto Velho, Rondonia Territory, Brazil. Resistivity profiles are the most usefull procedure to detect the limits of the paleovalleys. The results of seismic refraction and magnetic method data are discussed. Gravity and thermometry have not been applied in the area.
