Since publication of psoriasis treatment efficacy evaluation according to PASI (Psoriasis Area and Seve¬rity Index, i.e. indicator of extent and severity of psoriasis) in the year 1978 the technical possibilities of skin lesions imaging háve changed significantly. The digital photography improved, it is possible to measure the surface of lesions by computer, to evaluate the colour changes by colorimetry and to measure the skin thick-ness by ultrasonography. The higher is the quality of evaluation systems, the lower is their availability. In spite of that (or therefore) the evaluation of psoriasis by PASI remains the most convenient and the most used method in practice. It combines the theoretical knowledge and practical experience with a properly trained dermatologist eye.

        Key words: psoriasis evaluation - PASI and variations - SPASI - NAPSI