Spiral computer tomography (CT) has become a widely accepted clinical tool in the diagnosis of acute pulmonary embolism. The accuracy of computed tomography in diagnosing pulmonary embolism has increased over the past 10 years, parallel to technological improvements. However, as with most imaging techniques, interpretative pitfalls may occur for a variety of reasons. These include technical problems caused by respiratory motion artifact, improper bolus timing, streak artifact, and patient body habitus. In addition, misinterpretation of normal bronchovascular anatomy may lead to an erroneous diagnosis. This article discusses the various diagnostic pitfalls and methods to minimize and overcome them.