Nowadays the diagnosis of pulmonary embolism (PE) is based on a "diagnostic strategy" rather than a single test. The first step, after identifying patients with suspicion of PE, is to establish the pre-test clinical probability. Several scores are available to make a standardised and reproducible assessment of the clinical probability and these, therefore, represent valuable diagnostic tools. Indeed, it is the clinical probability that guides further investigation. In patients with low or intermediate clinical probability, PE can be safely ruled out by a negative D-dimer in approximately one-third of patients without additional imaging. In the case of a positive D-dimer or high clinical probability, CT pulmonary angiography is now the recommended imaging technique. However, lower limb venous compression ultrasound and ventilation/perfusion scans remain useful in patients with contraindications to CT; mainly those with renal insufficiency. In the presence of readily available and strongly validated diagnostic strategies, the challenge for the future will probably be better identification of patients in whom PE should be suspected.