The aim of the present study was to investigate the influences of acute water and land exercises on pain, state anxiety and salivary cortisol concentration in chronic low back pain (LBP) patients. Ten myofascial LBP patients participated in the experiment. Their mean age was 60.2 (SD : 9.0) yrs, and their mean duration of pain was 5.6 (3.7) yrs. The water and the land exercise programs consisted of the same physical movements, and prescribed according to the intensity of ratings of perceived exertion (RPE) 11. The heart rate of the participants was measured during exercise to monitor exercise intensity. Results showed that the mean heart rate during exercises (except Warming up and Cooling down) were 88.1±1.6 bpm for water exercise, and 97.0±2.1 bpm for land exercise (p<0.01) . Significant decreases were found in pain score (visual analogue scale ; VAS, p<0.05) and state anxiety (p<0.01) after water exercise. Salivary cortisol concentration showed a significant increase after water exercise (p<0.05) . No significant changes were shown after land exercise in VAS, state anxiety and salivary cortisol concentration. From these results, we suggested that acute water exercise has the benefit in chronic LBP patients of decreasing pain and state anxiety compared with acute land exercise. In addition, salivary cortisol concentration might be much more influenced by exercise intensity than physical or psychological stress such as pain and anxiety.