The prevalence of diabetes has been reported to be rapidly increasing in both rural and urban India. [2] An oral antidiabetic drug (OAD) is the first line of drug treatment for Type 2 diabetes. However, the progressive nature of Type 2 diabetes usually requires a combination of two or more oral agents in the long term. Safety and tolerability often limit the optimal use of OADs. [3] According to the World Health Organization (WHO), an adverse drug reaction (ADR) is defined as "a noxious, unintended, and undesirable effect that occurs as a result Research Article Background: Diabetes mellitus is a major healthcare problem in India. Pharmacovigilance of antidiabetic drugs is crucial in detecting adverse drug reactions (ADRs)and providing feedback to physicians on their possibility. In India, few reports are available on the ADR profile of antidiabetic agents. Objectives: This study aims to detect frequency and total burden of different ADRs due to oral antidiabetic drug (OAD)use in a diabetes outpatient in a medical college in Eastern India. Materials and Methods: An observational study was conducted on Type 2 diabetes mellitus patients on oral antidiabetic agents, attending Diabetes Clinic of a Tertiary Care Teaching Hospital in West Bengal between April and September 2013. Details of adverse event history, history of medication suspected of having caused the ADR were recorded in the format followed in the Pharmacovigilance Programme of India. The causality relationship was assessed by the World Health Organization-Uppsala Monitoring Centre criteria. Results: A total of 1000 patients were screened, of which 276 were suspected of having at least one ADR. On causality assessment, 43 of these 276 cases had insufficient evidence about causality and were excluded from the analysis. Out of the remaining 233 patients, 275 suspected ADRs were detected. Among them, metformin contributed 51% of total ADR reported, in the form of dyspepsia and diarrhea, followed by glimepiride-induced hypoglycemia. Vogliboseinduced dyspepsia, pioglitazone-induced pedal edema were also common. Conclusions: ADRs due to OADs is a frequent problem. Few multicentric studies are needed for a strong antidiabetic drug ADR database in India.