An 11-year-old spayed female dog was diagnosed with gallbladder mucocele (GBM), characterized by excessive mucin production that led to gallbladder distension and posed a risk for severe complications. Given these risks, current treatment guidelines recommend surgical intervention, with cholecystectomy being the preferred therapeutic approach. Furthermore, the dog presented with an adrenal gland mass, demonstrating hypertension and markedly elevated levels of metanephrine and normetanephrine, raising suspicion of pheochromocytoma without evidence of invasion or metastasis. This situation enhanced the viability of adrenalectomy as a treatment option. Histopathological analysis revealed the presence of a neuroendocrine tumor, potentially secreting catecholamines. Notably, this case illustrates a rare occurrence of both mucocele and pheochromocytoma in a dog. The dual surgical procedures of cholecystectomy and adrenalectomy were performed using advanced surgical techniques and required intensive postoperative care. The surgeries were successful, and the patient was discharged without complications. As of three years following the surgery, the patient continues to thrive without recurrence or significant health issues, highlighting the effectiveness of this surgical approach in m...