Hypoglycemia due to treatment with oral anti-hyperglycemic agents (OHAs) is a major clinical problem in patients with type 2 diabetes mellitus. The aim of the present study was to evaluate the risk of hypoglycemia due to OHA use by using the Japanese Adverse Drug Event Report (JADER) database. To this end, reports of hypoglycemia events included in the JADER database between 2004 and 2012 were analyzed by calculating the reporting odds ratio (OR). The Medical Dictionary for Regulatory Activities Preferred Terms was used to identify hypoglycemia; 254392 reports were found in the JADER database, of which 13269 were excluded because the age and sex of the patient were not reported. Finally, 241123 reports were analyzed. Among OHAs, sulfonylureas showed the highest adjusted OR (adjusted OR, 10.13; 95% confidence interval, 9.08-11.26). The adjusted ORs for meglitinides, biguanide, thiazolidinedione, alpha-glucosidase inhibitors, and dipeptidyl peptidase-4 inhibitors were significantly lower than that of sulfonylureas. The adjusted OR of meglitinides (3.17; 95% confidence interval, 2.23-4.36) was significantly higher than that of alpha-glucosidase inhibitors or thiazolidinedione. We observed no difference between the adjusted ORs for biguanide, thiazolidinedione, alpha-glucosidase inhibitors, and dipeptidyl peptidase-4 inhibitors. Data mining of the JADER database was useful for analyzing OHA-associated hypoglycemia events. The results of our study suggested a low risk of hypoglycemia associated with biguanide, thiazolidinedione, alpha-glucosidase inhibitors, and dipeptidyl peptidase-4 inhibitors in clinical practice.