A ten-year-old castrated male dog was presented due to a two-day history of constipation and tenesmus. At physical examination, the dog was depressed and unresponsive. Aggressive behavior was elicited by deep abdominal palpation and a mass was detected during the examination. Imaging studies evidenced a large jejunal mass. The lesion (6 cm in diameter) was surgically removed. The histopathology report gave a diagnosis of completely excised intestinal carcinoid. The patient recovered well from the procedure and was scheduled for adjuvant chemotherapy. The dog received four doses of carboplatin (300 mg/m2) every three weeks without showing signs of toxicity. The dog is still in remission after 18 months and is reassessed on a three-month schedule. This report represents the first description of long-term control of intestinal carcinoid in the dog and the first of adjuvant chemotherapy for this rare and aggressive neoplasm.