Conductive cellulose-based hydrogels have attracted much research interests owing to their high conductivity, biocompatibility, cost-effectiveness, environmental sustainability, flexibility, excellent mechanical properties, Chemical or physical properties of conductive cellulosic hydrogel can be designed to change in response to external stimuli. The combination of such unique features makes them promising candidates for different practical applications, including electronic devices and gas sensors. In the present work, a novel multi-functional hybrid hydrogel was fabricated via a facile two-step process. The flexible, self-healing, and electro-conductive hydrogels were successfully prepared by incorporating conductive nanomaterials (Graphene oxide or Reduced graphene oxide) into carboxymethyl cellulose networks crosslinked by citric acid. The chemical structure and morphology of the resulting conductive nanocomposite hydrogels were characterized using FTIR and SEM. The effect of the conductive nanomaterial contents on the mechanical, rheological, and electrical properties of the hybrid hydrogels was studied. The self-healing efficiency of the prepared hydrogels was evaluated by comparing tensile strength, breaking stress, and storage modulus of the original and healed samples. The FTIR finding confirmed that the 3D CMC conductive hydrogels are formed as a result of intra- and inter-molecular hydrogen bonding among their constituents. Morphological studies demonstrate highly porous interconnected hydrogels with pore sizes of 100–200 µm. It was found that the mechanical strengths of the CMC hydrogels are significantly enhanced by the incorporation of GO/RGO into the hydrogel network. The tensile strength of CMC-GO and CMC/RGO hydrogels are up to 2.3 times and 2.15 times stronger than the CMC hydrogels (85 KPa), respectively. Rheological results show a more stable hydrogel network with dominant elastic behavior. In addition, the multi-functional hydrogels exhibit excellent self-healing ability, with about 91.2 %, 94%, and 93% healing efficiency in tensile strength, tensile strain, and storage moduli, respectively. The self-healing capacity of the hydrogels is endowed by the reversible hydrogen bonds in the abundant oxygen-containing functional groups and ionic interactions between oxygen-containing functional groups existing in both CMC and the conductive agents. The CMC-RGO hydrogels show maximum electrical conductivity of 4.4 × 10-2 S/cm and about 68% recovery of the electrical properties after self-healing. CMC-RGO hydrogel sensors demonstrate high sensitivity and desirable stability upon exposure to ammonia gas. With the combination of such superior features, the developed conductive CMC-RGO hydrogels have great potential for practical applications in gas sensors.