This paper presents a robust gas identification technique for tin oxide (SnO2) gas sensors. The proposed technique generates a unique spike pattern or signature for each sensed gas, irrespective of its concentration. The proposed gas identification technique is insensitive to drift in the sensor baseline resistance. Furthermore, its calibration requires a single measurement to be made for each targeted gas. The proposed spike-based gas identification technique has been implemented in TSMC 0.18 mum CMOS technology and validated using experimental data from a fabricated in-house 4 times 4 SnO2 gas sensor array. Reported results reveal a 10% increase in correct gas detection rate.