The main goal of the presented study is the development of two agrofibres – hemp/flax and hemp/hemp shive reinforced hybrid biocomposites based on waterborne polymer matrix system – blends of biodegradable polyhydroxybutyrate (PHB) and poly(vinyl alcohol) (PVA). The correlation between agrofibre ratio and mechanical characteristics of hybrid agrofibre reinforced biocomposites has been established. The positive hybrid effect and optimal results in terms of mechanical strength of hemp/flax biocomposites have been found in 4:1 ratio. The elaborated hybrid biocomposites are considered biodegradable in soil, their mass loss is found to be ≥ 52 % … 54 % from initial mass during 5 months.