PURPOSE: This study aimed to assess the relationship between the severity of radiographic features and pain and function in patients with knee osteoarthritis (KOA). METHODS: Seventy-eight subjects (14 men, 64 women) with KOA, between the ages of 41 and 83 years (mean age, 61.29 years), were included. All the subjects diagnosed with KOA were scored for severity of radiographic KOA according to the Kellgren-Lawrence (K/L) grade, visual analogue scale (VAS), knee joint range of motion (ROM), Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), maximum muscle power (MMP), and sit-to-stand (STS) and one-leg standing (OLS) tests. Associations among the K/L grade, diagnosis, pain, and function were examined by correlation analysis. RESULTS: There were no significant differences between the K/L grade, and the VAS, STS test time, and WOMAC scores (p>.05). There were no significant differences between the K/L grade, bilateral ROM, MMP, and left OLS test time (p>.05). However, there was a significant difference between the K/L grade and right OLS test time (p<.05). The K/L grade was negatively correlated with the left OLS test time(r=-.24, p<.05) and with the right OLS test time (r=-.307, p<.01). CONCLUSION: These results suggest that radiographic KOA was not associated with pain, knee MMP, ROM, and STS test time, but had a weak negative correlation with OLS test time.