To document the frequency of the different acquired cardiac diseases in the referring area of the University of Zurich, records of 474 dogs were retrospectively analysed. Most common were valvular diseases, predominantly atrioventricular valve endocardiosis (49.4%), myocardial diseases, predominantly dilated cardiomyopathy (21.1%), pericardial effusion (12.4%), mainly due to neoplasia or idiopathic pericarditis, and cardiac neoplasia without pericardial effusion (7.0%). Rare to very rare diagnoses were dirofilariosis (2.5%), endocarditis (1.1%, only 2 of these valvular), hypertrophic cardiomyopathy (0.6%) and infectious pericarditis (0.4%). Arrhythmias were found in 145 dogs, mainly tachyarrhythmias, and most commonly associated with dilated cardiomyopathy. Relevant concomitant diseases were tracheobronchial collapse and hyperadrenocorticism in dogs with mitral endocardiosis. Knowing prevalence and causes of the various cardiac and the complicating non-cardiac diseases with clinical similarities is important for formulating diagnosis and differential diagnosis.