In this study, we demonstrate the growth of TiO2 coated ZnO nanorods by chemical vapor deposition process (CVD) followed by nano-cluster deposition (NCD). The ZnO nanorods are coated uniformly by TiO2 vapors forming porous shell. The surface morphology and structural properties were investigated by using field emission scanning electron microscopy (FESEM), energy dispersive spectroscopy and X-ray diffraction (XRD). The grown TiO2 coated ZnO nanorods were used for the fabrication of gas sensor for the detection of H2 gas. The sensing results clearly show the effect of TiO2 thickness on the ZnO nanorods. The sensitivity of 43.3, 72.9, 79.9, 88.9, and 58.49% were obtained for 0, 10, 20, 20, 30 and 35 min respectively at 320 °C for 500 ppm H2 concentration. The effect of thickness on the sensitivity was investigated.