Insulinomas, or beta-cell tumors, are the most common neoplasm of the endocrine pancreas and the most common cause of hypoglycemia in dogs over 5 years of age. As such, insulinoma is an important differential to rule out in dogs presenting with weakness, transient collapse, or seizures. Rarely, cases present with peripheral neuropathies characterized by proprioceptive deficits and depressed reflexes. In the following case, a 7-year-old Cocker Spaniel presented to its regular veterinarian with intermittent seizures. The patient was initially treated for idiopathic epilepsy before being presumptively diagnosed with insulinoma by a new general practitioner. The owner was then referred to Cornell University Hospital for Animals for further diagnostics and treatment. This paper describes the pathophysiology of the disease and current treatment methods.