The present study was aimed to examine the occurrence and influencing factors therapeutic duplication (TD) of medications for anxiety disorders by analyzing the relevant prescription data. In this study, the prescription data issued on March 19, 2008 in domestic medical institutes were utilized. TD was defined as more than two medications under the same therapeutic classification per prescription based on the Anatomical Therapeutic Classification (ATC) code. The assessment of TD was performed based on the number of cases and on the ratio determined. To identify the influencing factor of TD, the variables related to the differences in the TD ratio were analyzed based on the results of the Chi-Square test conducted with the variables; patients, medical institutes, diseases, and treatments. The number and ratio of TD were determined to be 1,333 out of the total of 19,219 anxiety disorder cases, and 6.94%, most cases involving benzodiazepine derivatives, respectively. The TD ratio was found to be higher in relation to males than to females. Patients with national health insurance benefits have a higher TD ratio compared to the medical-aid beneficiaries. The TD ratios were highest in clinics, psychiatry divisions, and Gyeongsang district. The TD ratio of the cases with more than two anxiety disorders was found to be higher than that of the cases with only one anxiety disorder. As the number of medications per prescription increased, the TD ratio was shown to have become gradually higher. In conclusion, in order to prevent TD, the concurrent DUR system should be implemented. The prescribers and pharmacists must be educated regarding duplicated medications to promote the safe and effective use of medicines, without unnecessary TD.