Thermoplastic starch has been obtained from corn starch and glycerol. The TPS obtained has been physico-chemical and mechanically characterized. Addition of natural latex has probed to decrease the kinetics of water absorption of the composites, although its effect on water uptake, crystallinity and mechanical properties was negligible. Composite materials obtained thorough reinforcement of the TPS matrix with sisal and hemp strands have been prepared and characterized. Incorporation of the natural fiber strands, independently of type and content, caused the reduction of VH-type structures. The results demonstrated that both tensile and flexural strength improved with the percentage of reinforcement fibers. Despite having similar mechanical properties, hemp strands provided composites with better mechanical properties that those obtained with sisal. This effect is assigned to the better fibrillation obtained during the mixing of the TPS with the hemp strands, and points out the mechanical anchoring as the main cause of the enhanced mechanical resistance.