Twenty-four equations for estimating evaporation and/or evapotranspiration were compared with measured Piche evaporation. At least 1728 months of records from 12 Peruvian stations were analyzed in this study. Computer programs were developed to work this study and the results were compared by plotting. It has been found that the equation that best fits the Piche evaporation in the low elevation stations in Peru is Christiansen's formula (ET2) which was used as a base for his formula for Class A pan evaporation (EVC).