Three ways of data pretreatment which can be used as part of a deconvolution procedure are shown. One way consists of subtraction of a straight line from the processed curve so that the resulting curve starts and ends with a zero value. The second way accomplishes the same result by multiplying the curve by the appropriate window, while the third way synthesizes the background current by interpolation with a cubic spline which yields the same result. Calculations on simulated differential pulse polarography curves performed with the software package MATLAB were undertaken. All three methods should be kept in mind and used according to the shape of the signal and the level of the available software package.