The paper is devoted to the preparation of a material based on isotactic polypropylene (PP) and cellulosic filler for additive manufacturing. Used microcrystalline cellulose was treated by polypropylene-graft-maleic anhydride (PP-g-MA) in toluene solution. This method of modification had a compatibilizing effect on the composite structure. The filament samples of neat PP and PP composites with treated by two methods and untreated cellulose were obtained by extrusion. Comparing technological properties of different filament types, it was stated that PP-g-MA modification conduced to lower shrinkage and uniform diameter of a filament. The filament was employed to develop 3D polymeric devices with predefined geometry and porosity by fused deposition modelling with a prototyping machine.