Atrial fibrillation (AF) is the most commonly encountered arrhythmia in clinical practice. AF frequently accompanies common conditions such as hypertension, chronic heart failure, and valvar or ischaemic heart disease, and is an important sequela of cardiothoracic surgery. Echocardiography has a unique and important role in the assessment of cardiac structure and function, risk stratification, and increasingly in guiding the management of AF. Because of its recognised value, echocardiography has become established in guidelines for management of AF and utilisation of echocardiography has increased, particularly of transoesophageal echocardiography to guide direct current cardioversion or detect cardiac sources of embolism. Even more recently the development of intracardiac echocardiography has led to real-time guidance of percutaneous interventions, including radiofrequency ablation and left atrial appendage closure procedures for patients with AF. Transthoracic echocardiography readily identifies important underlying conditions that predispose to AF, including left ventricular systolic dysfunction caused by dilated cardiomyopathy, left ventricular hypertrophy caused by hypertension, valvar heart disease particularly rheumatic mitral stenosis or pericardial disease.