Cervical lymph node metastasis is one of the most important predicting factors that influence the prognosis of oral squamous cell carcinoma. Correct diagnosis on cervical lymph node metastasis is essential in determining the extent of operation and treatment modality. So we investigated a clinico-statistical evaluation on cervical lymph node metastasis in 183 patients who were diagnosed with oral squamous cell carcinoma at the Department of Oral and Maxillofacial Surgery in Kyungpook National University Hospital, from January 1st, 1999 to December 31st, 2007. The following results were obtained : 1. Among 183 patients who were diagnosed with oral squamous cell carcinoma, 149 were male and 49 were female. The average age of the patients was 61.8 years old. 2. Patients with advanced T classification showed higher incidence of cervical lymph node metastasis than those with lower T classification. 3. Patients with less differentiated tumors had higher tendency of manifesting cervical lymph node metastasis than those with more differentiated tumors. 4. Sensitivity and specificity on PET/CT was 87.5% and 58.3% respectively. PET/CT showed higher sensitivity and lower false-negative values than those of CT or USG. 5. The 5 - year survival rate of all the oral squamous cell carcinoma patients appeared to be 63.2% By N classification, patients in N0 stage showed a higher survival rate than patients in N1 or N2. 5 - year survival rates according to the modality of neck dissection were as follows in increasing order: no neck dissection group, MRND group, SND group, and RND group.