Early and accurate diagnosis of congenital heart diseases is paramount to assess if surgical/interventional or medical treatment is indicated and to define long-term prognosis. In this lecture we will focus on the echocardiographic diagnosis and treatment options for pulmonary stenosis (PS), subaortic stenosis (SAS) and ventricular septal defects (VSD). PS is one of the most common congenital heart defects in dogs and a minimally invasive transcatheter procedure is available to treat this condition (i.e. balloon pulmonary valvuloplasty, BVP). But careful echocardiographic assessment of patients with PS is mandatory to define which cases have an indication for BVP. In SAS, a medical or interventional procedure has not yet been identified that prolongs survival, but during this lecture, we will discuss the available treatment options and when they should be attempted. Finally, we will review VSD in dogs focusing on the echocardiographic diagnosis and classification of this congenital defect.