Atrial fibrillation (AF) is the most common arrhythmia encountered in clinical practice. Despite the common association of AF with cardiovascular disease, some patients can be classified as ‘lone AF’. The latter is essentially a diagnosis of exclusion, and should be preceded by careful evaluation, including thorough collection of medical history, physical examination, blood pressure measurement, laboratory tests, ECG, echocardiography and, possibly, chest x-ray and exercise testing. Lone AF patients were initially thought to have a good prognosis with respect to thromboembolism and mortality, compared with the general AF population, but more recent data suggest otherwise. This review focuses on the clinical epidemiology and management aspects of lone AF, as well as various associated novel risk factors, such as familial, genetic and socioeconomic factors, alcohol, sports activity and biochemical markers.