During the last decade cellulose fibre based composites were investigated with intensity, as such lightweight materials are expected to contribute substantially in energy and material savings in mobility application. High performance and lightweight composites were prepared through thermal forming of intermingled polypropylene-cellulose (lyocell) fibre slivers. The concept of intermingled fibres results in composites with superior mechanical properties compared to composites prepared by extruder, because the fibres can be oriented along the direction in which the drawing process was performed. The lyocell fibres function as reinforcement and influence the mechanical properties. Different types of fibres sliver were used with different share and orientation of lyocell fibres. The tensile strength and E-modulus were determined as function of the lyocell fibre share and orientation. Also the influence of water/moisture was investigated. Lyocell has benefits such as low density and sustainability, but its reinforcing properties are reduced in presence of water. In water saturated state, the ultimate tensile strength and E-modulus were reduced, which can be explained by the deteriorated adhesion between the lyocell fibres and the polypropylene matrix. The mechanical properties of the composites were characterised by Dynamic mechanical thermal analysis (DMTA). The results given form a scientific basis for a more detailed understanding of the behaviour of cellulose reinforced composites in lightweight materials.