The poor survival rates of patients with carcinoma of a tongue, despite of modern therapy, is well recognized. One of the most important prognostic factors is status of the cervical lymph nodes. There have been a long-standing debate about the treatment of cervical lymph nodes in early-stage tongue cancer. There are two major treatment opinion. The one is surgical excision of primary tumor with prophylactic neck dissection, simultaneously, and the other is to delay the cervical therapy until cervical lymph node is palpable. Recently we have experienced the early cervical metastasis in three patients who had been diagnosed as a carcinoma of the tongue. They were T1, T2 lesion and no palpable node was found. But histopathologic examination showed the occult metastasis or delayed cervical metastasis was occured. By the review of literature and clinical experience, we could conclude the prophylactic neck dissection offers a better chance for success than therapeutic neck dissection of palpable lymph nodes, in case of oral tongue cancer.