Pulmonary embolism (PE) in childhood is rare and correlated with high morbidity and mortality, and diagnosis is often delayed. This is a case report of a 15-year-old boy presenting with chest pain, dyspnoea and pain in the right inguinal region, who was found to have multiple pulmonary emboli secondary to a 14 cm long femoral venous aneurysm. Two weeks before he had seen his GP due to dyspnoea, where asthma was suspected. He was treated with low molecular weight heparin but developed recurrent PE and underwent vascular surgery. Clinical suspicion to PE is the key to a rapid diagnosis, treatment and survival.