The purpose of the study was to detect if increases in functional levels for patients with osteoarthritis show differences between an aquatic exercise program and a land-based exercise program. Forty-six subjects between the ages of 45 and 70 years participated in 1 of 2 exercise groups. Pre- and posttest measurements included knee range of motion (ROM), thigh girth, subjective pain scale, and time for a 1-mile walk. Both exercise groups showed a significant (p < 0.05) increase in all measurements between pre- and posttests. There were no significant differences between the aquatic exercise group and the land-based exercise group pertaining to knee ROM, thigh girth, and time for a 1-mile walk. Subjective pain levels were significantly less in the aquatic group when compared with the land-based group. This study concludes that both aquatic and land-based exercise programs are beneficial to patients with osteoarthritis.