A 31-yr-old male Sumatran orangutan (Pongo abelii) presented with 14 yr of chronic purulent nasal drainage and cough with intermittent exacerbation of symptoms requiring systemic antibiotic treatment. He was diagnosed with a cystic fibrosis (CF)-like condition. Evaluation consisted of bronchoscopy with bronchoalveolar lavage, culture, and computed tomography scanning of the sinuses and chest. Although the presence of low fecal elastase activity increased the suspicion for a diagnosis of CF, pilocarpine iontophoresis with sweat collection and analysis (“sweat testing”) was inconclusive. Medical management included twice-daily nebulization with bronchodilators and alternating month inhaled antibiotics, pancreatic enzyme replacement therapy, and simethicone as needed. Sinopulmonary and gastrointestinal symptoms improved substantially with treatment. Several years later, the animal died acutely of colonic volvulus. Necropsy and histopathology confirmed CF-like lung disease with chronic air sacculitis.