The research has been conducted in utilising plastic and organic wastes from coconut fibre (CF), plastic of polyetilene tereftalate (P), coconut shell (CS) and unsaturated polyester resin (UPS) to manufacture a composite panel. Water uptake of composites with single reinforcement containing 50% from those materials and combination of those materials was studied. For degradation testing, a composite containing (by weight) plastics (30%), coconut fibres (30%), coconut shells (5%) and unsaturated polyester resin (35%) was used as this composition was optimum. The specimen was immersed in water (stable condition) and alternating immersed for one day and dried one day (fluctuating condition) for 7, 15 and 30 days before tested in tension, bending and impact. The water uptake of a more heterogen material (P30,CF30,CS5,UPS35) was higher than a composite with single reinforcment. The tensile, bending and impact strength decreased (degraded) with increasing conditioning time, however the degradation in stable condition was higher than in fluctuating condition.