Pulmonary embolism is a difficult entity to diagnose clinically and pulmonary angiogram has been the gold standard for the diagnosis. Our objective was to evaluate the usefulness of electron beam (Ultrafast) CT scan in aiding the diagnosis of such an entity, thus avoiding an invasive procedure. Between April 1995 and March 1996 we prospectively studied 20 patients with clinical suspicion of pulmonary embolism by conventional perfusion scan of the lung, by invasive pulmonary angiography and by contrast enhanced electron beam CT scan. Simple statistic correlation between the 3 methods was obtained in regard to sensitivity and specificity utilizing the pulmonary angiogram as the gold standard. The sensitivity and specificity of contrast enhanced electron beam CT scanning was 95 per cent and 100 per cent respectively. The correlation of positive and negative result of all three imaging modalities was 60 per cent. Contrast enhanced electron beam (Ultrafast) CT scan is a good alternative diagnostic modality for pulmonary embolism.