We herein describe the case of a 29-year-old woman with type 1 diabetes from 10 years of age who developed adult cyclic vomiting syndrome. Beginning at 25 years of age, she was frequently hospitalized for stress-induced vomiting. Her vomiting episodes developed acutely and remitted after severe vomiting of more than 30 times a day for a few days. The vomiting periods were accompanied by leukocytosis with a predominance of neutrophils, high blood pressure and fever. In addition, it was noted that her levels of both adrenocorticotropic hormone and antidiuretic hormone during the vomiting attacks increased and subsequently dramatically decreased immediately after symptom improvement; therefore, she was diagnosed with adult-type cyclic vomiting syndrome in accordance with the diagnostic criteria of Rome III, a system developed to classify functional gastrointestinal disorders. Though glycemic control had improved with continuous subcutaneous insulin infusion therapy, the vomiting frequency increased due to the failure of drug treatments and general psychotherapy to terminate the vomiting attacks, making discharge difficult and greatly interfering with everyday life. Eventually, hypnotherapy and miniature garden therapy were prescribed, which significantly reduced the vomiting frequency, making it possible to discharge her from inpatient medical care. In the treatment of this patient with type 1 diabetes and adult-type cyclic vomiting syndrome, continuous subcutaneous insulin infusion therapy and comprehensive psychotherapy were effective.