We present average polarization profiles for 20 pulsars at 1720 MHz made with the 100-m Effelsberg radio telescope. All four Stokes parameters were appropriately delayed in a linear dedisperser to correct the interstellar dispersion on-line. Our sample includes a number of complex profiles which were observed polarimetrically for the first time at a high frequency, with the aim of describing their frequency evolution. Classification of the corrected profiles is attempted according to the empirical pulsar model described earlier by Rankin(1990).