The optimal diagnosis strategy for pulmonary embolism (PE) in the emergency department (ED) remains complex. This review summarizes PE diagnosis with clinical presentation, decision rules and investigations for acute PE. This review was performed using studies published between January 1, 2010, and September 1, 2023. PE should be considered in ED in patients with chest pain, shortness of breath, syncope or signs of deep veinous thrombosis. Definitive diagnosis of PE relies on thoracic imaging, with the use of chest tomographic pulmonary angiogram or ventilation-perfusion lung scintigraphy. To limit the continuous increased use of chest imaging, the clinical probability should be the first step for PE workup. The pulmonary embolism rule-out criteria (PERC) can rule out PE at this stage. If not, for low or intermediate probability, several clinical decision rules have been validated, either by ruling out PE on clinical signs, or by raising D-dimer thresholds (YEARS or PEGeD [Pulmonary Embolism Graduated D-Dimer] criteria) or by combination of these different rules. It is recommended that patients with a high clinical probability of PE should undergo chest imaging without the need for D-dimer testing. The PE diagnostic approach can be tailored in specific populations such as pregnant, younger, COVID-19, or cancer patients. PE diagnosis workup illustrates the complexity of modern probabilistic-based approaches of decision-making in medicine. It is recommended to use a Bayesian approach with the evaluation of clinical probability, then order D-dimer if the PERC rule is positive, then adapt the D-dimer threshold for ordering chest imaging using clinical decision rules.