Objective <p>The purpose of this study was to evaluate the diagnostic performance of the waist-to-arm ratio (WAR) for screening the sarcopenic obesity (SO) in older adults.</p> Methods <p>A cross-sectional study was conducted among Korean older adults aged over 65 years. Data were extracted from the Korean National Health and Nutrition Examination Survey (KNHANES) 2023 years. Sarcopenia was defined as handgrip strength &lt; 28&#xa0;kg for males and &lt; 18&#xa0;kg for females and appendicular skeletal muscle mass index (ASMI) &lt; 7.0&#xa0;kg/m² for males and &lt; 5.7&#xa0;kg/m² for females. Obesity was defined as waist circumference (WC) ≥ 90&#xa0;cm for males and ≥ 85&#xa0;cm for females. SO was defined as having sarcopenia and obesity simultaneously. WAR is calculated as waist circumference divided by mid-upper arm circumference (WAR = WC/MUAC).</p> Results <p>The accuracy levels of WAR for screening SO (as assessed by area under the curve) were 0.895 in males and 0.771 in females. WAR cutoff values for screening SO were calculated to be 3.44 for males and 3.32 for females. The sensitivities were 100.0% in males and 84.2% in females. The specificities were 71.6% in males and 59.4% in females. </p> Conclusion <p>The present study demonstrates that WAR was a simple and effective index for screening the SO in older adults in Korea, especially in males.</p>