One of the main difficulties in the research of lectins is the absence of an adequate technique for their specific and routine detection. Here, we present a photoreactive carbohydrate-probe which could help to overcome this problem. The probe was comopsed by joining four segments: (i) a carbohydrate moiety, (ii) the digoxigenin tag, (iii) the photoreactive cross-linker and (iv) the lysyl-lysine backbone. After incubation with lectins in the dark, the probe can be activated and cross-linked to the lectins by illumination. The result is a lectin with covalently incorporated digoxigenin tag. Such a labelled lectin can be easily identified using anti-digoxigenin antibodies in a Western blot technique. This method is of high specificity and sensitivity and enables direct detection of lectins in complex mixtures, even whole cell homogenates.