Cellulose is widely recognized as the most abundant renewable material on earth. It possesses many interesting properties such as high mechanical performances and environmentally friendly characteristics. Thus, the uses of nano-sized cellulose in composites have been shown increasingly in recent years. Specifically, nanofibrillated cellulose (NFC) has received special attention in materials science because of its unique properties such as high mechanical properties, high surface area, and applicable rheology. We have used graphene oxide (GO) and reduced graphene oxide (RGO) as functionalized graphene materials to combine with nanocellulose with the purpose of creating new materials with improved properties. For example, we have found that an addition of graphene into nanocellulose paper increased not only tensile strength and Young's modulus but also mechanical performance in high humidity and high temperature condition (at 80% of relative humidity and 80 oC). Besides, electrical conductivity of the cellulose composites has been improved significantly with just 0.3 wt% of graphene loading. At this graphene content, the conductivity was electrical conductivity of 4.79 x 10-4 S m-1, which is well above the antistatic value. It should also be noted that our method of combining the graphene materials with nanocellulose suspension has created stable graphene/nanocellulose suspension, which have been stable for year. We believe that the developed NFC/RGO composite materials can find potential uses as conductors, antistatic coatings, and electronic packaging, especially where high moisture is present and high mechanical properties/electrical conductivities are needed.