A computer simulation program in conjunction with an instrument systems analysis program lead to the conclusion that microwave radiometry working in concert with thermal infrared systems could detect petroleum product pipeline leaks. The utilization of these systems from an airborne platform would result in a low falso alarm rate and a high probability of leak detection. A demonstration experiment was designed to test the simulation program. This demonstration was carried out in west Texas along three different pipeline sections with eighteen individual leak circumstances. All data, airborne and ground, was reduced, correlated and analyzed to demonstrate remote sensor capabilities. It was found that the apparent microwave (13.7 GHz) temperature of a leak increases significantly compared to surface material containing no oil. Also, a soil containing oil caused a decrease in polarization contrast. Thermal infrared showed a warm area surrounded by a cool halo. When these circumstances all occurred together a leak was identified, proving the correctness of the original computer simulations. (Modified author abstract)