A comparative study of retention in different systems of flow control, that provide linear dependence with temperature of column’s head pressure, is performed by numerical simulation considering multistep (or multiramp) PTGC as the mosí general situation. Calculation algorithms for each flow control mode are developed on the basis of general retention equation and the only additional hypothesis that certain geometric parameters of the column remain practically constant along the program. Procedieres are individually contrasted with experimenta prior to application. The comparative view indicates that simple correlations ccmnot be obtained between retention times and temperatures in two different pressure Controls or pressure programs. It seems that numerical procedures are unavoidable when it is required the conversión of retention data from one chromatographic system to another with the same stationary phase.