BACKGROUND Squamous cell carcinoma (SCC) of the tongue is one of the most common cancers in the oral and maxillofacial region. To provide clinical evidence for selective neck dissection in management of cN0 patients by analyzing the characteristics and correlation of factors of occult cervical lymph node metastases (OCLNM) in patients with SCC of the tongue. METHODS From 2002 to 2006, 100 consecutive patients with SCC of the tongue were reviewed by analyzing the characteristics of OCLNM, diameter of the tumor, T classifications, depth of invasion, forms of growth, pathological grade and degree of differentiation. RESULTS The rate of OCLNM in 100 patients with SCC of the tongue was 22%. The most common region with OCLNM was level II in the ipsilateral neck, followed by levels I and III. There were 51.61% (16/31) of OCLNM in level II and 87.10% (27/31) of OCLNM in levels I - III. There was no significant correlation between the diameter of tumor and OCLNM (P > 0.05). OCLNM was statistically significantly correlated with the depth of invasion, forms of growth, pathological grade and degree of differentiation (P < 0.05). The rate of occult metastases increased with the increased pathological grade, the decreased degree of differentiation and the increased depth of invasion. CONCLUSIONS The most common regions with OCLNM in cN0 patients with SCC of the tongue were levels I - III in the ipsilateral neck. Supraomohyoid neck dissection should be the elective treatment to the neck in patients with cN0 SCC of the tongue by consideration of the clinical and pathological factors for the depth of invasion, forms of growth, pathological grade, and degree of differentiation.