Objective The purpose of this study was to determine the differences in emotional distress among three groups of inpatients with type 1, obese type 2, and non-obese type 2 diabetes during hospitalization. Methods The 42 participating inpatients were divided into three groups: type 1 diabetes (n=11), obese type 2 diabetes [body mass index (BMI) ≥25 kg/m(2); n=24], and non-obese type 2 diabetes (BMI <25 kg/m(2); n=7). The Problem Areas in Diabetes (PAID) scale, which is a self-administered questionnaire to assess emotional distress in the patients with diabetes, was performed at admission and discharge. Results The total PAID score was similar and tended to improve during hospitalization in all three groups, although there were differences among the groups in the scores of particular questions. At admission, the score of the question "worrying about low blood sugar reactions?" was significantly different among the three groups and highest in the patients with type 1 diabetes. At discharge, the score of "not accepting diabetes?" was significantly different among the three groups and highest in the patients with non-obese type 2 diabetes, while that of "feeling unsatisfied with your diabetes physician?" was significantly different among the three groups and highest in the patients with obese type 2 diabetes. The score of "feelings of deprivation regarding food and meals?" significantly worsened in the patients with obese type 2 diabetes during hospitalization compared with the patients in with non-obese type 2 diabetes. Conclusion The characteristics of emotional distress during hospitalization varied among the patients with the three types of diabetes, thus emphasizing the importance of tailoring support according to the type of diabetes.