Composites made from wood residues and biomasses, together with either conventional polymers such as polypropylene (PP) and their recyclate streams or with the new emerging biopolymers such as polylactic acid (PLA), were compounded and injection moulded. Mechanical properties and biodegradation analyses were undertaken. The addition of wood flour/sander dust (SD) and wood fibres (WF), to the PP, with suitable compatibilizer, increased the flexural and tensile modulus and strength, indicating a good bond between the fibres and matrix. The tensile and flexural strengths were decreased with the addition of wood fillers, additives and biomasses to a PLA biopolymer blend. Such biomasses and additives increased the biodegradation of the PLA blend, and some control over biodegradation rates was achievable.