The vast majority of animals with congenital heart disease present with an audible murmur; thus, auscultation is the initial key diagnostic test. Nearly all congenital defects have a systolic murmur - except most notably a patent ductus arteriosus (PDA), which has a characteristic continuous murmur. However, some rare defects may have no murmur, such as a reversed/balanced shunt. Recent reviews of congenital heart disease are available. In very young puppies and kittens, flow murmurs are common. They are difficult to differentiate from a congenital defect on auscultation alone and thus create a diagnostic dilemma for the clinician when a murmur is discovered, and cause problems on how best to advise the owner. Murmurs in puppies and kittens; Patent ductus arteriosus; Aortic stenosis; Pulmonic stenosis; Ventricular septal defect; Mitral dysplasia; Atrial septal defect; Tricuspid dysplasia; Tetralogy of Fallot; Atrioventricular septal defect; Cor triatriatum dexter; Cor triatriatum sinister (CTS) and supravalvular mitral stenosis (SMS); and Other congenital defects are discussed.