The aim of the research is the estimation of residual fertilizer value of granulated organic-mineral fertilizers (OM1, OM2, OM3, OM4, OM5 and OM6) formed from spent mushroom substrate (SMS). OM1, OM2, OM3, OM4 and OM6 were supplemented with mineral fertilizers (urea, ammonium nitrate, ammonium sulphate, single superphosphate, high-potassium salt) before the process of granulation. Two composts were used for their production; four fertilizers (OM1, OM2, OM3 and OM4) were formed from composted SMS (called SMC), and two fertilizers (OM5 and OM6) were formed from a composted mixture of SMS and sewage sludge. The evaluation of their residual fertilization value was based on a two-year microplot experiment. Fertilizer combinations used in the experiment include: unfertilized control object, composted SMS (SMC) and six granulated organic-mineral fertilizers: OM1, OM2, OM3, OM4, OM5 and OM6. These fertilizers and the compost were used in two doses of N corresponding to 100 kg · ha^-1 and 200 kg · ha^-1. Samples of soil for the chemical and physical soil analyses are collected every year after harvests (methods: C_org after dry combustion, N_tot by a modified Kjeldahl method). Results of the analyses were processed statistically by using Statgraphics 4.0. Organic-mineral fertilizers, based on SMC (and optional with sewage sludge) supplemented with mineral fertilizers, have a positive residual influence on the increase in C_org content (4.80-5.99 g · kg^-1) and N_tot content (0.43-0.53 g · kg^-1) in the soil. Ratio of C/N was in the range from 9.43 to 11.75. These fertilizers are an excellent source of nitrogen and organic carbon for agriculture. The increase in the level of fertilization causes the increase in the content of N_tot, and C_org in the soil. The production of these fertilizers could be a solution to management of SMS and sewage sludge in agriculture.