Objectives : Oral pain without identifiable oral mucosa lesion is probably multifactorial origin, which include burning mouth syndrome (BMS), oral candidiasis and so on. The aim of this study was to analyze the characteristics of oral pain without identifiable oral mucosa lesion and to evaluate treatment outcome of those patients. Materials and Methods : We reviewed 50 patients without identifiable oral mucosa lesion who were complaint of oral pain. The patients were analyzed according tothe sites, associated symptoms, laboratory tests and fungus culture. The questionnaire included questions on their current diseases, smoking and alcoholic history, psychological factors, and symptoms. Results : The average age of patients was 60 years old. The most frequently involved site was tongue (92%), followed by palate, lower lip, oropharynx, and gingiva. 60% of the patients has psychological disorder as self reported. Culture for Candida was positive in 36% of patients and serum zinc deficiency was present in 60% of patients. Serum iron, vitamin B12, hemoglobin, folic acid deficiency were present in 6-2% of patients. Seventeen patients (65%) with BMS and twelve patients (66%) with oral candidiasis were improved after treatment. Conclusion : We recommend oral candida culture to oral pain patients without oral mucosa lesion. Zinc supplementation of zinc depletion patients may be helpful whereas other laboratory tests have no diagnostic values.