Nowadays the developing of effective methods for radioisotopes removal from aqueous solutions is carried out in different directions of chemical technology, such as, coagulation, extraction, precipitation, membrane and sorption techniques. Method of sorption considered as the most promising because of simplicity, accessibility, cheapness and efficiency. Sorbents based on natural polymers derived from plant material, such as plant wastes or residues of agricultural complex, are of a special interest as alternative sorbent as they are environmentally friendly, biologically inert, readily available and cheap. Another important advantage of the application of modified plant materials as sorbents for radioactive elements is its ease of disposal - for instance, by chemical or thermal degradation with subsequent storage of the obtained ash residue. Selective biosorbents based on lignocellulose (LC) materials can be produced by modification of the plant polymer matrix with specific inorganic compounds that characterized by high sorption ability towards certain ions. Different types of inorganic materials have been proposed for the removal or concentration of different radionuclides from water solutions, such as, activated, hydrous metal oxides, titanates and silicotitanates, zeolites, clays, etc. Long-lived 137Cs and 90Sr with half-life of 30 and 29 years respectively are characterized by a high radiotoxicity. Cesium is chemically similar to potassium and strontium is chemically similar to calcium and tend to deposit in human body casing different illnesses. Removal of radioactive cesium and strontium from liquids ensures health security and environmental protection. It is known that ferrocyanides of d-metals ([FC] M) and hydrated antimony pentoxide (HAP) are characterized by high sorption ability towards cesium and strontium respectively. During modification of plant matrix with solutions [FC] M and HAP under hydrothermal conditions the formation of complex lignocellulose-inorganic sorbents LC-[FC] M and LC-HAP take place. The dependence between the concentration of modifiers in the initial solution, size of modifier nanoclusters and sorption properties of sorbents was established. It was found out that increasing the concentration of modifier results in the increase of modifier content in the bulk of organic carriers and the sorption capacity of obtained materials towards cesium and strontium also increases. Increasing the concentration of modifier in the initial solution from 1 to 10 g/l leads to enlargement of inorganic particles, thus the predominant size of modifier agglomerates significant increases. It was also found out that the increasing of [FC] M and HAP concentrations in initial solutions over 8% do not affect the modifier content and sorption properties of composite biosorbents. Samples of LC-[FC]M with the content modifier 4.5% in the bulk carrier are characterized by the maximum value of cesium removal efficiency 94% and distribution coefficient 7·103 ml/g. For LC-HAP with HAP content 3.3% the values of the same parameters towards strontium are 93% and 2·103 ml/g respectively. Despite that the maximum efficiency of modifier mass use of for radionuclide sorption corresponds to the samples of lignocellulose-inorganic materials with the content of [FC] M about 2.0 – 2.5% and for HAP is about 1.8 – 2.0%. Thus it was shown that changing the modifying conditions it is possible to affect the composition and the size of modifier nanoclusters, its content in the bulk of carrier and sorption capacity of biosorbents towards radionuclides. Obtained materials can be successfully used in radiochemistry and analytical chemistry for the concentration of cesium radionuclides for further research, in ecology for effective removal of radionuclides from low-level radioactive solutions and water treatment, as enterosorbents with sorption, radioprotective and antioxidant properties for the application in medicine for the radionuclide injuries treatment; in veterinary as a feed additive that will reduce the adsorption of radionuclides in the gastrointestinal tract of animals with the aim to obtain normative pure products.