The results obtained from the underhood inspection portion of the Oregon motor vehicle emission inspection/maintenance (I/M) program are reported. The underhood inspection for tampered or missing emission control equipment is an important element of Oregon's I/M program. The rate of emission control equipment disconnections are contrasted with federal survey results. These summaries indicate that this type of inspection shows reduced vehicular emission control tampering when compared to nationwide averages. This indicates that inspecting for onboard emission control equipment is an effective technique and contributes in achieving the goal of clean air.