In the present work, a Ranque-Hilsch vortex tube (RHVT) is modified by suggesting a novel vortex chamber at inlet. The performance of the modified vortex tube is studied experimentally. Suggested lengths for the vortex chamber are 10, 15, and 20 mm and the vortex chamber diameters are 12, 16, and 20 mm. All vortex chambers with different lengths and diameters are tested experimentally at variable inlet conditions. It's found that the vortex chamber diameter has a dominant effect on the performance compared with the vortex chamber length. The results are compared with that obtained by a conventional vortex tube. The results show that the vortex chamber gives an enhancement in the isentropic efficiency reach to 15.9 %. The results for a vortex chamber of 15 mm length and 20 mm diameter has the best performance.