Subsequent cervical metastasis after treatment for primary tumor has much influence on the prognosis of T1, T2N0 tongue cancer. We investigated clinically the subsequent cervical metastasis in the cases of T1, T2 tongue cancer treated during the period from 1979 to 1990. The results were as follows. 1) In the incidence of subsequent metastasis, there was little difference between T and T. We have to be careful about potential risk of even T1. 2) The cumulative five-year survival rate of the group of subsequent metastasis and that of the group of cervical metastasis on first examination were almost the same. Subclinical metastasis was implicated as the possible cause of subsequent metastasis. 3) We had no way to evaluate 'subclinical metastasis' clinically. 4) Onset of subsequent metastasis was within one year after treatment and that result of treatment was pessimistic one. But the patients with subsequent metastasis after more than two years had good survival rate. Careful follow-up should be mandated to detect cervical metastasis as early as possible especially during the first two years.