The presented paper is focused on the effect of the wood flour on the rheological and mechanical properties of elastomer blends. The mentioned wood flour comes from the production of wood pellets. Wood flour can be used as an alternative plasticizer in the elastomer mixture due to the lignin content. Lignin is the less polar than cellulose and acts as a chemical adhesive agent. The wood flour and other lignocellulosic fibres can be easier incorporated as a plasticizer with other ingredients into a rubber compound. Plasticizers (also called softeners, extenders or process oils) are the additives for polymers with a low molecular weight. An increasing content of a plasticiser usually leads to decrease in viscosity of the rubber mixture, and therefore, the processability can be improved. The influence of the wood flour and its different particle sizes on rheological properties of elastomer blends and mechanical properties (hardness, tensile properties) of vulcanizates were studied. The achieved results show the possibilities of plasticizer replacement for studied wood flour in the elastomer blend. The results of this research can also bring environmental benefits in the form of removing petroleum products from the production of rubber. This research work has been supported by the Operational Programme Integrated Infrastructure, co-financed by the European Regional Development Fund by the project: Advancement and support of R&D for "Centre for diagnostics and quality testing of materials" in the domains of the RIS3 SK specialization, Acronym: CEDITEK II., ITMS2014+ code 313011W442.