A retrospective study was done to analyse the diabetic cases in a secondary care hospital in Salem for a period of six months for evaluating drug-drug interactions. A total of 148 prescriptions were collected and analysed for drug-drug interactions. The obtained data were cross referenced to each other getting the maximum data. The 148 cases were classified according to gender wise and age wise and the maximum number of patients coming under the age group of 41-60. Then the cases were classified according to the number of drugs prescribed per prescriptions, in that cases in which 8-12 drugs are prescribed had found to have maximum number of drug interactions. Total number of drugs prescribed in 148 prescriptions is 204 in that 76 drugs are prescribed in generic names and 128 drugs are prescribed in brand names. From the total 148 prescriptions 69 prescriptions are showing drug-drug interactions in that 40 were male patients and 29 were female patients, in that Glipizide is interacting with 10 drugs, Insulin is interacting with 6 drugs, metformin is interacting with 3 drugs and Pioglitazone is interacting with 1 drug. It may be concluded that total number of drug interactions were found to be 46.62% in 148 prescriptions, in that the significant interactions are found to be 37%.