Abstract: Remote sensing for the detection of pest damage is an important element in forest management, This study describes the application of Landsat-5 Thematic Mapper digital data, using the Perceptron image analysis system, for the detection of western spruce budworm damage on Douglas fir stands near Cache Creek, British Columbia, Canada. Digital analysis included channel ratios and maximum likelihood classification. Best results were obtained from a colour composite of one classified (Red), TM3 (Green) and TM5 (Blue) channels that clearly showed the pest damage areas. This study demcnstrates that the application of Landsat-5 Thematic Mapper digital data using the perceptron image analysis system, is an excellent remote sensing technique suitable for the delineation of damage areas caused by western spruce budworm on Douglas fir stands.