This study compared the effects of 2 types of water exercise programs on balance ability in the elderly. Thirty healthy elderly persons (60.7 +/- 4.1 yr) were randomly assigned to a deep-water-running exercise (DWRE, n = 15) group or a normal water exercise (NWE, n = 15) group. The participants completed a twice-weekly water exercise intervention for 12 wk. Exercise sessions comprised a 10-min warm-up on land, 20 min of water-walking exercise, 30 min of water exercise while separated into NWE and DWRE, a 10-min rest on land, and 10 min of recreation and relaxation in water. Postural-sway distance and tandem-walking time were decreased significantly in DWRE. Postural-sway area was decreased significantly in NWE. In both groups, simple reaction times were significantly decreased. The findings of this study show that a water exercise program including deep-water running is much better than normal water exercise for improving dynamic balance ability in the elderly.