Objectives: To document the incidence and pattern of c-kit protein expression & mutation in adenoid cystic carcinomas. Materials and Methods: Twenty-five cases of adenoid cystic carcinomas of the major and minor salivary glands and the upper and lower respiratory tract were subjected to the immunohistochemical study for ckit(CD117 ; Dako). Nineteen cases of them were analyzed for mutations in exon 11 and exon 17 by PCR-SSCP, and in cases of need, by DNA sequencing. Results: Twenty-three cases (92%) showed c-kit expression, but none showed mutations in exon 11 and exon 17. The expression was restricted to the inner luminal cells in all tubular types and most of cribriform adenoid cystic carcinomas, while the staining was diffuse in all solid variants and two cribriform types. Conclusion: C-kit expression was common in adenoid cystic carcinomas, regardless of their origins. Although genetic bases await further studies, a clinical trial of tyrosine kinase inhibitors in adenoid cystic carcinomas, especially in solid variants, is considered encouraging.