PURPOSE We tried to evaluate the difference in the expression of carbonic anhydrase (CA) III and heat shock protein (Hsp) 70 between laryngopharyngeal reflux disease (LPRD) and non-LPRD patients. MATERIALS AND METHODS The study involved 28 patients who underwent laryngeal microsurgery due to benign laryngeal disease from March to August 2008. Reflux symptom index (RSI) and reflux finding score (RFS) were measured for each person, and they were assigned either to the LPRD group (n=10) or non-LPRD group (n=18). Tissue samples were obtained from the mucosa of posterior commissure, and immunohistochemistry (IHC) staining of CAIII and Hsp70 was performed. The IHC scores were measured and compared with clinical features including RSI and RFS. RESULTS Total 10 patients were assigned as LPRD group, and 18 patients were as control group. The mean IHC score of CAIII and Hsp70 was 1.70 ± 1.06 and 1.90 ± 0.88, respectively, in LPRD patients, whereas the mean IHC score of CAIII and Hsp70 was 0.78 ± 0.73 and 0.94 ± 0.87, respectively, in non-LPRD patients. The difference between two groups was statistically significant (p<0.05). CONCLUSION CAIII and Hsp70 expressions were higher in LPRD patients that in non-LPRD patients, suggesting the possibility as one of biomomarker in LPRD diagnosis.