The paper presents the fabrication and characterization of thin-film sensors for gas-sensing applications. The use of nanomaterials to detect gases at low concentrations have been very effective due to their low cost, easy customization, high stability and repeatability of the responses. Carbon nanotubes, due to their exceptional electromechanical characteristics, were used as a dopant to mix with tin-oxide to form the resultant nanocomposites. Tin-oxide was synthesized using stannous chloride as the precursor material via hydrothermal method. An optimization process in terms of electrical conductivity and mechanical flexibility dictated the quantity of nano-fillers in the composites. The resultant thin-films were used to detect low-concentrations (1–10 ppm) of methane gas. The characterization of these sensors were studied using COMSOL simulations and other techniques like X-Ray Diffraction. The results displayed here validates the potentiality of the CNTs/SnO ₂-based sensors for real-time gas-sensing applications.