Megaesophagus is the generalized esophageal dilation and hypomotility resulting from a segmental or diffuse motor dysfunction. The main clinical sign is regurgitation through the mouth or nostrils after ingesting water or food. To be classified, this pathology takes into consideration the moment in which the disease developed (congenital or acquired), and its etiology (idiopathic, primary or secondary). Based on anamnesis, clinical and complementary exams it is possible to reach a diagnosis. Thus, this report aimed to share with the academic and professional community the clinical evolution of the patient that will be described below, as well as the approaches that were adopted. This is a two-month-old male shit-tzu dog that arrived at the clinic complaining of reflux of milk through the nose, regurgitation after ingesting wet food, and head tremors. After a detailed anamnesis, together with laboratory and imaging tests, the diagnosis of congenital megaesophagus was confirmed. Thus, a treatment that allowed the clinical improvement of the animal was established.