The experiment was conducted during two years (2008-2009) in Leškovice (the Czech Republic) on potato cv. 'Finka and Katka’ at 0.45 x 0.80 m spacing. In the experiment 2 types of mulch were used: textile mulch and grass mulch. The use of grass mulch decreased the attack of potato haulm by Phytophtora infestans by 8.2% as compared to the control variant (without mulch) and textile mulch decreased the late blight attack on tubers by 2.6% (as compared to the control variant). Grass mulch influenced the number and size of tubers, increasing the number and the weight of tubers of over 56 mm and on the other hand decreasing the weight of tubers of under 40 mm as compared to the control variant. The yield of ware potatoes was higher in the plots with mulches on the average in 2008-2009 (as compared to non-mulched control variant where the yield was higher by 6.0 t·ha⁻¹ in grass mulch and by 5.7 t·ha⁻¹ in textile mulch).