We examined the settlement preferences of leeches by analysing colonization patterns on artificial substrates. The intention was to check whether the type of material, texture and size of artificial substrates would influence the abundance of leeches. To test substrate type preferences, we used the following nine artificial substrates: polyester, polycarbonate, aluminium, glass, rubber, steel, polyethylene, ceramics and polypropylene. In addition, substrates of different textures (structural vs. smooth) and sizes (900, 400, 100 cm 2 ) were used. We found that rubber, polyethylene and aluminium were most frequently chosen by the leeches. Surface structure and size of the objects were other factors which determined substrate selection by these organisms. Leeches more readily inhabited rough surfaces and the surfaces of smaller-sized objects. The species composition of leech assemblages on analysed artificial substrates was dominated by predatory taxa of the genus Erpobdella and Helobdella.