A 10 month old, intact male West Highland White Terrier, presented to the Cornell University Hospital for Animals Emergency Service in February 2012 for lethargy, pale gums, and abdominal distention. He was previously diagnosed with a supravalvular pulmonic stenosis in November 2011. Pulmonic stenosis (PS) is the third most common congenital cardiac defect in the dog. Currently, balloon valvuloplasty is the treatment of choice for correction of a PS. It is minimally invasive and associated with relatively low risks. There are four aspects of the patient that should be considered when determining if a balloon valvuloplasty is indicated. This paper will discuss the diagnostics, surgical plan and the technique used for a balloon valvuloplasty in order to correct a pulmonic stenosis.