Transesophageal electrophysiologic study (TEEPS) is a semi-invasive method widely used for evaluation of symptoms related to arrhythmia. In this study, we aimed to determine the accuracy of TEEPS in the diagnosis and differentiation of mechanisms of supraventricular tachycardias (SVTs) by comparing results of transesophageal and intracardiac electrophysiologic studies. We performed TEEPS and a subsequent radiofrequency ablation (RFA) procedure in 76 patients. Indications of TEEPS were risk assessment for Wolff-Parkinson-White syndrome in 32 patients and diagnosis and differentiation of tachycardia mechanisms in 44 patients. The procedure was well tolerated in all patients. Positive predictive value of TEEPS in our study was 91% for differentiation of SVT mechanisms. The results suggest that TEEPS is safe, useful and effective in the evaluation of symptoms related to arrhythmia, in differentiation of mechanisms of SVTs, and finally in defining the treatment options of SVT. The technique also provides an opportunity for risk assessment and deciding the treatment modality in Wolff-Parkinson-White patients.