Upper limb thromboembolism is a relatively uncommon clinical syndrome that mainly affects elderly patients with cardiovascular comorbidities. Atrial fibrillation has been recognized as the main cause. However, many other cardiac and non-cardiac disorders have been identified as possible sources of upper limb thromboemboli. From a clinical point of view, upper limb thromboembolism represents a vascular emergency so that the delay in diagnosis and treatment is highly likely to imply dramatic complications. Therefore, prompt recognition and treatment is mandatory as well as identification and correction of risk factors. Despite its clinical relevance, data in literature are lacking and sparse, most likely because upper limb thromboembolism has a relatively low prevalence in the general population. We sought to write a simple but comprehensive review of this topic, thus proving cardiologists and critical care physicians with the essential tools to recognize and treat upper limb thromboembolism, identifying and correcting also its risk factors and causes.