This pilot study aimed to evaluate the effect of an aquatic therapy program on physical fitness, postural balance and pain in patients with chronic low back pain after lumbar disc herniation. The sample consisted of seven individuals who were evaluated and subjected to the treatment program in group, for 20 sessions. The instruments used were: a) Time up and Go Test (TUG), b) March Speed Test, c) Rolland Morris Disability Questionnaire, and d) Visual Analogue Scale (VAS), which were applied before the program starts and after the tenth and twentieth session. Regarding the results, there was no significant improvement in any of the variables studied, although it was registered a slight increase in walking speed (0.98 m/s, 1.03 m/s and 1.05 m/s), slight decrease in the TUG (13.2 s, 12.6 s and 11.5 s) and pain intensity (6.42, 5.57 and 5.28). Therefore, the proposed Aquatic Physical Therapy program promoted a little improvement on postural balance and on intensity of pain. However, these results should be viewed with caution since there was no significant difference. Thus, it is suggested to continue investigations using this therapy with larger number of subjects.