Dual‐energy x‐ray absorptiometry (DXA) is a nondestructive technique that can potentially measure specific components of whole‐body composition in free‐living and lab‐raised animals. Our aim was to test the ability of DXA to measure the composition of a common arvicoline rodent, the northern red‐backed vole (Clethrionomys rutilus). We used a DXA apparatus to obtain measurements of fat mass (FM), lean mass (LM), bone mineral content, bone mineral density, and fat‐free mass (FFM) in carcasses of free‐living and lab‐raised voles. We then used chemical carcass analysis to derive predictive algorithms for actual values of FM, total body water, total protein, total mineral, LM, and FFM. Unexplained error in the equations for all voles grouped [...]