The present study investigated factors associated with knee pain and functional limitation in knee OA patients. Subjects were 109 Japanese males who were newly diagnosed with knee OA at three university hospitals over a 1-year period. Knee pain and functional limitation in walking and climbing and/or descending stairs were selected as outcome measures. To assess factors associated with outcomes, we calculated odds ratios (OR) using logistic regression analysis. Taller height (> or =163 vs. <163 cm) showed a negative association with knee pain, "Pain on walking": OR = 0.08, 95% confidence interval = 0.01-0.79; "Pain on stairs": 0.25, 0.08-0.82. A significant characteristic related to a lesser degree of functional disability was alcohol consumption ("Waking distance": 0.34, 0.14-0.84; "Help on stairs": 0.21, 0.09-0.51). In the present study, knee pain was associated with shorter height in male Japanese patients with knee OA. Functional limitation was associated with no consumption of alcohol.