Soil base saturation values of Ortho Dark Red Latosol, Red Yellow Latosol and Humic Red Yellow Latosol can be described by Johnson's S B curves on a log-normal distribution. Percentil points, moments and least squares methods were used to estimate the y and g parameters to fit this distribution. All three methods give good results and data transformation to normal distribution was efficient. The least squares method simplifies the calculation and does not require special table.