A novel gas-sensing system based on a dynamic nonlinear response is reported to enhance the selectivity toward sample gases using a single detector. A periodic temperature change was applied to a semiconductor g-as sensor and the resulting conductance of the sensor was evaluated by fast Fourier transformation (FFT). The dynamic nonlinear response to the sample gases was further characterized depending on the frequency of the temperature change. The characteristic sensor response under the application of a temperature change was theoretically simulated by considering the kinetics of gas molecules on the semiconductor surface. (C) 2004 Elsevier B.V. All rights reserved.