The imbalance between epithelial cell growth and inhibitory factors may cause human epithelial cancer. The dysregulation of growth inhibitory effect of TGF-β1 has been recognized in a variety of carcinomas. This study aimed to investigate the expression of TGF-β1 type II receptors(TβR-II) in the carcinogenesis of oral squamous cell carcinoma(OSCC). Six cell lines established from OSCC in the department of Oral Pathology, Yonsei University College of Dentistry were used. DNA was extracted from harvested cells by phenol-chloroform method. Polymerase chain reaction (PCR) was done with each primer of exon 3, 4, 5, 6 of TβR-II gene. PCR products were inserted to cloning vector (pGEM-T easy vector) and then analyzed to automatic DNA sequencing analyzer. Reverse transcriptase-PCR (RT-PCR) was performed to confirm the mRNA expression of TβR-II gene. Western blotting was performed to detect the expression of the TβR-II protein. As results, a frameshift within a polyadenine region of exon 3 was found in YD-8 cell line. In YD-17 cell line, a missense mutation at codon 238 of exon 4 was found, suggesting the alteration of amino acid from asparagine to aspartic acid. TβR-II mRNA was detected in all cancer cell lines, but it was slightly decreased as compared to that of normal oral mucosal cells. In Western blotting, no TβR-Ⅱ protein was detected in all OSCC cell lines. These results suggested that the altered regulation of TGF-β1 function might play a role in the development of OSCC.