To determine the prevalence and determinants of physical activity in older Koreans, we assessed KNHANES-V, a cross-sectional and nationally representative survey conducted by the Korean Ministry of Health and Welfare. We also compared population estimates based on age, gender and major chronic conditions that the elderly frequently reported. In the data from KNHANES-V, 1964 out of 6193 were aged 60 and older. Being physically active was defined as participating in moderate physical activity for at least 30 minutes, 5 days a week or in vigorous physical activity for at least 20 minutes, 3 days a week. 70.6% older adults are never physically active; 36.4% of seniors walk daily (defined as 30 minutes a day, at least 5 days per week). Only 12.5% of older adults are as physically active as the American College of Sports Medicine (ACSM) recommended. There was a significant gender difference in ACSM's recommended Physical Activity (PA) (Chi-square F=21.22, p<.0001), moderate PA (Chi-square=3.57, p<. 05), vigorous PA (Chi-square=24.02, p<.001), and recommended walking (Chi-square=24.13, p<.001). In vigorous activity, age and education were significant factors that affected males (p<.05) but not females (p<.05). In moderate activity, education was significant influence for male only. In walking, education (p<.001) and perceived health (p<. 05) were influenced in men, but age (p<.01) and perceived health (p<.05) were influenced in women. In general, PA participation was affected by age (OR: 0.94, 95% CI: 0.88-1.00), perceived health (OR: 2.30, 95%CI: 1.39-3.80), and limited activity (OR: 3.96, 95% CI: 1.21-12.94) in males, yet, none of these factors affected PA participation in females. In conclusion, to promote physical activity participation in the older Korean population, different strategies should be introduced according to gender.