Purpose of review: This review will focus chiefly on recently published studies utilizing air-displacement plethysmography (i.e. BOD POD) in geriatric populations. This innovative technology has been available commercially since 1995. As the test procedure is relatively easy to perform and quick, it may provide an improvement in body composition testing, especially in older individuals with poor ambulation and health. Recent findings: This review will explain in a concise and detailed manner the underlying principles of air-displacement plethysmography specifically related to the BOD POD. Second, it will review the studies using this new technology in comparison with more commonly used techniques (hydrostatic weighing, dual energy X-ray absorptiometry, deuterium oxide, multi-compartmental models) for body composition analysis in geriatric populations. Third, it will provide a direction for future studies. Summary: A review of the current body of literature in which air-displacement plethysmography was used is beginning to emerge with a clear picture. Although this technique is still new, it appears that air-displacement plethysmography is a valid and reliable alternative to more traditional body composition techniques, as indicated by small mean differences between techniques. This has special implications in a geriatric population because traditional techniques are difficult to perform in individuals with joint pain, ambulation issues, and overall poor health. © 2004 Lippincott Williams & Wilkins.