Diabetes is a major economic burden disease globallyThe geriatric diabetic cost economic studies in India are limited. Hence this study carried out with the objective to assess the various costs incurred during the geriatric diabetic treatment (COI model). METHODS: This was a prospective, cross sectional study conducted from July 2012-July 2014 in the General Medicine Department of Kasturba Medical College Hospital, Manipal, after obtaining ethical clearance. Cost details were obtained from hospital finance and pharmacy. The Descriptive statistical method was applied  RESULTS: A total of 475 cases were enrolled of which 52.42% had diabetes. Of this, 27.71% had DM alone, 6.82 % had DM associated renal disease (i.e.: 3.6% were DMAKI, 3.2% were DMCKD), 12.44% had other than renal DM complications (microvascular), 48.19% had both DMHTN, 4.81% had DMHTN associated complications.  The total cost incurred for the treatment of the disease and its related complications (DM alone, DMAKD, DMCKD, DM neurological complications, DMHTN & DMHTN) did not vary significantly [ I.e. Mean+ SD (INR): 16044.7 + 37740.06,  15374.51+ 11915.94,  14840.03+14124.05,  8395.35+ 16580.11,   27130.28 +   64934.04,   14430.5+  13113.78 ) . The cost of treatment (INR) appeared low due to varying factors like free screening or treatment for other symptoms, etc. The cost based on various factors were as listed - Medicine charge > Laboratory/diagnostic charges > Nursing charges > Material charges > Procedure charges > Professional charges > Admission related charges >Miscellaneous charges. CONCLUSIONS: This study clearly suggests that medicine expense is the highest cost factor in DM treatment. The second highest cost was laboratory followed by nursing costs. Research on pharmacoeconomic models like cost effective analysis (CEA), Cost minimization analysis (CMA), and Cost benefit analysis (CBA) by the pharmacist &the stakeholders  is essential to reduce the burden in geriatrics.  Lack of availability of direct non-medical cost was the limitation of this study