This community-based cross-sectional study was conducted to assess anthropometric characteristics and estimate the prevalence of undernutrition among older persons in rural Ballabgarh, Haryana, India. A total of 948 participants aged 60 years and above were examined. Their weight, arm span, mid-upper-arm circumference, triceps skinfold thickness, and calf circumference were measured using standard techniques. The prevalence of undernutrition was estimated to be 53.7% (95% confidence interval [CI] = 50.5-56.9). Logistic regression analysis was done to identify factors independently associated with undernutrition. In the assessment of anthropometric characteristics, the strongest correlation was observed between body mass index and mid-upper-arm circumference (r = 0.88; P < .0001). Receiver operating characteristic analysis showed that mid-upper-arm circumference has a higher ability (area under curve = 0.93; 95% CI = 0.91-0.96) of detecting undernutrition among older persons than triceps skinfold thickness and calf circumference. The high prevalence of undernutrition among older persons in rural India warrants major public health interventions.