Background: Visual estimation of age can be used as a measure of biological age (BA) and has become useful in predicting life expectancy. Objective: The aim of this study was to quantify the interrater agreement of experienced geriatricians in visual estimation of BA. Methods: In a prospective controlled study, 4 experienced geriatricians estimated the BA of 43 elderly subjects (mean age 82.5 ± 6.0 years) during a short standardized interview, using a checklist of age-associated changes in appearance, communication and mobility. Interrater agreement was calculated by analysis of variance and expressed as the intra-class coefficient of correlation (ICCC). Results: The ICCC of the BA estimation was 0.76 (p < 0.001). Within-subject standard deviation of the estimate was 3.4 years. On average, BA was 4.8 (±4.4) years lower than chronological age (p < 0.001). Conclusion: Visual estimation of BA based on a simple checklist has a good interrater agreement and therefore should be part of geriatric assessment.