Laryngopharyngeal reflux (LPR) may contribute to the development of laryngeal diseases including vocal fold leukoplakia. Clinical methods of determining LPR are limited. Pepsin, as an exogenous protein, is considered as a biomarker of LPR. The aim of the current study was, therefore, to detect pepsin by immunohistochemistry in the biopsies from patients with vocal fold leukoplakia, and by which, to determine the potential association of LPR and vocal leukoplakia. A total of 26 biopsies from patients with vocal fold leukoplakia were examined in comparison with 20 vocal fold biopsies from control subjects.