PURPOSE: The aim of this study was to investigate the effect of closed and open kinetic exercises on knee extensor strength and balance in patients with early stroke. METHODS: Thirty patients with early stroke participated in the study. Participants were randomly assigned to three groups: an open kinetic chain (OKC) exercise group (n=10), a closed kinetic chain (CKC) exercise group (n=10), and a control group (n=10). All participants received conventional physical therapy for 30 minutes. In addition, the two experimental groups (OKC and CKC) participated in a 30-minute knee strengthening training program. Training for the experimental groups was carried out three times a week for four weeks. Outcomes such as knee extensor strength and balance ability (Tetrax, Functional Reaching Test, Timed Up and Go Test) were measured before and after training. RESULTS: There were significant differences in knee extensor strength and balance ability between the pre- and post-treatment of all groups (p<.05). The improvement of knee extensor strength was significantly higher in the OKC group than in the other groups (p<.05), and the improvement of dynamic balance was significantly higher in the CKC group than in the other groups (p<.05). CONCLUSION: These results showed that both open and closed kinetic chain exercises are effective in the improvement of knee extensor strength and balance ability. This study suggests that open and closed kinetic exercise training is an effective training for strength and balance in patients with early stroke.