The vegetation experiment investigated the effect of municipal sewage sludge and farmyard manure on the yielding and chemical composition of potatoes of Irga cultivar, as well as selected physico-chemical soil properties. The soil was subject to the determination of pH, organic carbon content, total nitrogen, available P and K, and exchangeable cations. The yield of fresh and dry mass of potatoes and content of N, P, and K in the tubers were also determined. Moreover, the soil and potato tubers were subject to the determination of heavy metals (Cd, Cu, Cr, Fe, Mn, Ni, Pb, Zn). The conducted analyses showed high fertiliser value of municipal sewage sludge, approximate to that of manure. Its application had a positive effect on all the analysed soil properties, and resulted in a doubling the yield of potato tubers in comparison to the control object. As a result of the applied fertilisation with sewage sludge and manure, the content of heavy metals in potato tubers significantly increased in comparison to control. The content of Cd and Pb in potato tubers varied from 0.11 to 0.14 µg Cd kg^-1 FM, and from 0.03 to 0.15 µg Pb kg^-1 FM, and was considerably lower than the acceptable value (0.1 mg kg^-1 FW) pursuant to the EU Regulation, hence it posed no threat for the health of consumers. In reference to the possibility of accumulation of heavy metals in soil, it was evidenced that the analysed sewage sludge can be safely applied for a period of 27 years before the Pb content exceeds the limit for soils under agricultural use. In the case of other metals, the period is considerably longer, and for Cu it reaches 2340 years. In the conditions of application of manure, Pb content will exceed the limit after 87 years, and Zn after 4699 years.