The clinical picture of pulmonary embolism (PE) ist remarkably unspecific and one has to rely mainly on imaging techniques to obtain a reliable diagnosis. PE is not a primary disease but the complication of deep venous thrombosis (DVT), and thus there is a strong correlation between pulmonary embolism and venous thrombosis. Radiologic screening of these diseases is based on invasive and noninvasive tests. Chest X-ray has a low predictive value of 63% and helps mainly in ruling out other diagnoses such as pneumothorax or pneumonia. Chest computed tomography scanning with contrast may occasionally be useful in detecting large central emboli. Magnetic resonance imaging in PE has not yet been shown to be of great clinical value. Digital subtraction angiography has the potential advantage of allowing injections of smaller contrast volumes and is particularly useful in pulmonary hypertension. Cardiac and respiratory motion blur images and render interpretation difficult. Conventional pulmonary angiography is required for definitive diagnosis in a significant number of patients, especially when V/Q scan is non-diagnostic. Its morbidity and mortality is nowadays negligible. If these facilities are not available, they can often be obviated by venous studies searching for the presence of venous thromboses. Alternative modalities include contrast phlebography and venous ultrasound imaging. This last, newly developed technique combined with compression Doppler is safe and accurate, at least in the femoral and popliteal veins. Contrast phlebography remains the standard imaging method, is widely available, and demonstrates floating clots or thromboses with minor complications using non-ionic contrast media.(ABSTRACT TRUNCATED AT 250 WORDS)