Anthropometry is a technique in which simple measuring instruments are used to describe human form. By applying the measurement directly or through use of additional calculations, the practitioner can partition the body into fat and fat‐free components. Quantifying these two body spaces provides information on the amount and rate of change over time in whole body energy supply and protein mass. These data can then be used in association with other indices of energy and protein metabolism. Whereas anthropometry is simple, practical, and inexpensive, the technique is limited to a qualitative tool by several sources of error. A thorough understanding of the strengths, limitations, and appropriate applications of anthropometry is essential when applying the method in clinical practice. (Journal of Parenteral and Enteral Nutrition 11:36S‐41S,1987)