Background: Intensive insulin treatment is bothersome in obese patients with type 2 diabetes mellitus. High insulin dosages further increase weight gain and the risk of hypoglycemia. Glucagon like peptide-1 receptor agonists decrease the insulin need, cause weight loss and reduce the risk of hypoglycemia. There is limited data about the effect of exenatide on obese diabetics under intensive insulin regimens. Methods: This retrospective case series report the clinical outcomes of 23 obese (13 morbidly obese) patients with uncontrolled type 2 diabetes mellitus (Age = 59 +/- 10.44 years, body mass index 41.1 +/- 6.8 kg/m(2), HbA1c 9.9 +/- 1.5 %), under high dose (94.1 +/- 39.6 unit) intensive insulin. Exenatide twice daily was added for a mean follow-up period of 11.22 +/- 7.01 (3-30) months. Intensive insulin regimens were continued in 7 patients while the others were switched to basal insulin during the follow-up. Results: During the follow-up, mean HbA1c levels of the patients significantly improved (p = 0.019), along with the significant decrease in body mass index and the total insulin need (p < 0.001 for both). Baseline insulin dosages were significantly higher in the intensive regimen group (p = 0.013) while other demographical and clinical characteristics were similar. No significant difference was present between the groups regarding the alterations of HbA1c, body mass index and the reduction in total insulin dosages. Conclusion: Add on exenatide appears to be a rational treatment modality in uncontrolled obese patients with type 2 diabetes mellitus despite intensive insulin regimens. Further prospective randomized studies with longer follow-up periods are recommended.