Experimental investigations of mechanical behaviour of bedding of rape seeds were performed at four levels of moisture content (6, 9, 12 and 15%). Bulk density and pressure ratio of the bedding were determined with methods recommended by new standard Eurocode I. Deformation of the medium was also investigated in loading – unloading cycle of uniaxial compression. Stress – strain relationship was described with an elastoplastic model proposed by Sawicki. Modulus of elasticity and Poisson's ratio of the material were determined using linear phase of unloading cycle. It was stated that adopted model adequately described investigated process. Material properties as well as the model parameters were found strongly influenced by moisture content of seeds.