PROPOSE: Premature ejaculation (PE) is the most prevalent male ejaculation disorder. The premature ejaculation diagnostic tool (PEDT) was developed to systematically apply the DSM-IV-TR criteria in diagnostic PE. This study was designed to assess the validity of the Korean version of the PEDT as a diagnostic tool for PE. MATERIALS AND METHODS: The Korean version development of the PDET involved two stages: (1) Development of the initial language version through two independent forward translations and one backward translation. Discrepancies between the original English form and the first draft Korean translation were reviewed by the panel. Discrepancies between the original English form and the Korean translation were reviewed by the panel. (2) For psychometric validation and scoring system development, data was collected from men with and without PE based on clinician diagnosis, using DSM-IV-TR criteria. A total of 98 patients with a DSM-IV-TR defined PE and 100 men without PE were enrolled into the study and requested to complete the PEDT, which was translated into Korean. The PE patients were also requested to measure intravaginal ejaculatory latency time (IELT). The 50 men of no-PE group and all PE group were requested to come for a second visit to assess the PEDT's retest reliability. The results were analyzed statistically by SPSS version 12. RESULT: The mean age of the no-PE group and PE group were 43.4+/-9.2 and 51.6+/-9.0, respectively. The geometric mean IELT of the PE group was 115.37+/-78.14s. The number of men reporting IELTs of <1, 1-<2 and >2min were 28 (28.6%), 29 (29.6%) and 41 (41.8%), respectively. The Cronbach's alpha score of the Korean version of PEDT was calculated as 0.93, showing adequate internal consistency. The test-retest correlation coefficients of each item were higher than 0.72 and the correlation coefficients of the total score was 0.88. (P<0.001) Sensitivity and specificity analyses suggested a score of < or =8 indicated no-PE, 9 and 10 probable PE, and > or =11 PE. CONCLUSIONS: The Korean version of PEDT was highly effective in detecting the presence of PE. The result of our study supports its validity as a diagnostic instrument in the clinical setting.