The study is a continuation of studies aimed at the determination of the impact of chamber parameters and moisture content on densification of biological raw materials. The results of investigations on the impact of wheat straw compaction conditions on the parameters of the process and on the strength of the agglomerate are presented. The experiments were performed with the help of a universal strength tester, Zwick Z020/TN25, and a closed compression assembly (die) with three chamber diameters of 12 mm, 15 mm and 18 mm. The relationships between the density of the material in the chamber and agglomerate, the degree of compaction of the agglomerate, work effort on the compaction, coefficient of susceptibility of the material to compaction and the agglomerate mechanical strength and moisture content of straw for the three diameters of the chamber were determined. It was found that the densification parameters depend in varying degrees on moisture content of wheat straw and on the matrix chamber diameter. Increase in moisture content improves the susceptibility of material to agglomeration and worsens the quality of the agglomerates in terms of their strength.