Background: Exergaming, one of the most recognized virtual rehabilitation tools, has been shown to be useful for promoting physical activity and enhancing postural stability for neurologic conditions. However, studies with exergaming programs for patients with knee osteoarthritis (OA) are limited. Aims: We aimed to investigate the effects of exergaming given by visual and auditory stimulated assisted joint training device in addition to the conventional physiotherapy program on pain intensity, range of motion (ROM), functional status, kinesiophobia, proprioceptive acuity, muscle strength, and postural stability in patients with knee OA. Study Design: Randomized controlled clinical trial. Methods: Sixty patients (47 female, 13 male) with knee osteoarhritis aged 40–65 years (57.36 ± 7.26) who were at stage of two to three according to the Kellegren Lawrence radiological evaluation were included in the study. The patients were randomly divided into two groups as study group (conventional physiotherapy + exergaming) and control group (conventional physiotherapy). Electrotherapy and exercise program were applied to both of the groups along 5 days a week for 6 weeks but exergaming only applied to study group. ROM, pain intensity, proprioceptive acuity, kinesiophobia, muscle strength, and postural stability of the patients were evaluated at the beginning and end of the treatment. Results: In the intra-group analyses of all the assessments of the patients, there was a significant difference in the positive direction in both groups, except for the postural stability values. In the intra-group analyses of postural stability, there was a significant increase only in the study group. In comparison between the groups, proprioceptive acuity, ROM, functional status, and postural stability scores were significantly increased in the study group according to the control group; pain and kinesiophobia decreased significantly. Conclusion: In this study, the exergaming accompanied with conventional physiotherapy programs resulted more positive improvements on pain, ROM, postural stability, kinesiophobia, proprioceptive acuity, and functional status in patients with knee OA compared to the conventional physiotherapy program alone.