The study was carried out in 2003, in a micro-plot experiment established in the Experimental Garden of the University of Warmia and Mazury. Following our previous long-term field observations on the infestation of a number of field bean cultivars by black bean aphid, three cultivars were selected for the present study. The cultivars demonstrated different attractiveness to the pest insects: cultivar Tinos was preferred by aphids, cv. Dino was less readily chosen and cv. Nadwiślański was the least preferred variety. The computer analysis of leaf colour enabled us to distinguish between the cultivars. The three examined cultivars are different in the colour of leaves, although the differences between cv. Dino and Nadwiślański being nearly negligible, especially in terms of hue (H) and intensity (I).