Purpose : To investigate the immediate effects of transcutaneous electrical nerve stimulation(TENS) on the spasticity and the balance in the stroke patients. Methods : 26 subjects with spasticity over lower limbs were allocated randomly into two groups : (1) TENS group, (2) placebo-TENS group. TENS was applied on the both gastrocnemius for 60 minutes(100 Hz, 0.25 ms, 2 times sensory threshold). The modified Ashworth Scale(MAS) and Manual Muscle Tester were used to assess the spasticity of the ankle plantar flexors. Static balance under three conditions was measured by force-plate; in (1) the condition of standing with eyes opened, (2) with eyes closed and (3) the condition of standing on unstable surface with eyes opened. Results : When compared with the pre and post TENS application, TENS showed significant reduction of ankle spasticity in MAS and MMT measurement. Also, Application of high-frequency TENS improved the balance under three conditions. Conclusion : A single session of TENS to stroke patients could reduce spasticity and improve the balance.