목적: Benign paroxysmal positional vertigo involving the posterior semicircular canal (PC-BPPV) can be treated by receiving the canalith repositioning maneuver (CRM) once with a symptom resolution rate of 70-90%. However, repeated CRM may be beneficial in some group of patients with PC-BPPV. The aim of this study is to determine the efficacy of performing an additional CRM in the treatment of PC-BPPV by comparing the outcomes of receiving the CRM once or twice during a single session. 방법:This study was performed using a prospective, single-blinded, randomized study design. Sixty seven patients with PC-BPPV were randomly divided into two groups. A single Epley maneuver was performed in 35 patients (Group 1), while the Epley maneuver was performed twice in 31 patients (Group 2) with a time interval of 30 minutes without repeating the diagnostic test during a single treatment session. The results of treatment were compared between the two groups 24 hours and 1 week after the initial treatment using Dix-Hallpike maneuver. Resolution was defined as an absence of both vertigo and nystagmus. 결과:There were no differences in any clinical variables (age, sex ratio, affected side, and duration of symtoms) between the two groups at randomization. No statistically significant difference was demonstrated in the resolution rate between the two groups. The recurrence rate was 11.4% and 6.5% for the Groups 1 and 2, respectively, but no statistically significant difference was found. 결론:The Epley maneuver provides very high resolution rates in patients with PC-BPPV. An additional maneuver during a single session is not recommended in the treatment of patients with PC-BPPV.