The purpose of this paper is to present detailed information that may be helpful to others undertaking soil erosion and runoff studies. A general decription is given of the methods used for determining soil erosion and water losses from experimental plots. A detailed description is presented of the method for colleting a fraction of the total runoff, using slot divisors of the Geib type. An example is given with calculations showing soil erosion losses, occuring in one single day, from an experimental plot located in Ribeirão Prêto, on purple soil, (terra roxa legítima) and bearing coffee trees on a slope of 6.5%. The average values of soil density in runoff and the conversion factor from volume to weight of soil are also given so that determination of the weight of soil lost from the coffee experimental plot, could be made.