The identification of methods for uranium immobilization is important for decision-making on remediation of contaminated areas. Here we investigate the degree of uranium binding on peat sorbents chemically modified using humic acids (HA), zero-valent iron (ZVI), and aqueous ferric chloride. The peat was sampled in the territory of the sludge storage of low-radioactive wastes. In the laboratory, the uranium adsorption on natural peat reaches the maximum values of 86% after 8 hours in comparison with the 92% after 30 min on HA modified peat and 88.8% after 2 hours on aqueous ferric chloride modified peat. The improvement of the peat sorption capacity was confirmed within the three months field experiment using HA and ZVI. The results of the sequential extraction procedure confirm the participation of both modifiers in the processes of uranium sorption.