[Purpose] The purpose of this study was to assess the effects of home-based knee stretching exercises on knee range of motion (ROM) and gait speed in patients with knee osteoarthritis awaiting total knee arthroplasty. [Subjects] Thirty-six patients with severe knee osteoarthritis were randomly allocated to stretching (n=17) and control (n=19) groups. [Method] The subjects in the stretching group were instructed to perform home-based knee stretching exercises once a day for about 80 days, whereas the subjects in the control group were told to maintain their current level of physical activity. Outcomes assessed percentage changes in the total range of knee ROM in the supine position (S-ROM), pain, gait speed and knee ROM during gait (G-ROM). [Results] The stretching group showed significantly greater improvement in S-ROM, gait speed and G-ROM than the control group (control vs stretching; S-ROM, 0.4 ± 8.6% vs 9.5 ± 16.2%; gait speed, 1.6 ± 11.4% vs 11.6 ± 10.7%; G-ROM, 0.6 ± 15.2% vs 14.2 ± 14.6%; p<0.05 for all). Pain was significantly decreased in the stretching group compared to the control group (median values: -15.6% and 6.5%, p<0.01).