Military circumference equations are used to assess compliance of military personnel with body fat (BF) standards. The purpose of the present study was to determine the ability of military equations to correctly classify 62 women aged 40-60 yr (50.9 +/- 6.2, mean +/- SD) as overfat or underfat using underwater weighing (UWW) as the reference method and military BF standards as diagnostic cutoffs. Values for the mean +/- SD percent BF from UWW, Army, Marine Corps, and Navy equations were 29.5 +/- 7.1, 27.3 +/- 4.7, 25.7 +/- 5.8, and 30.3 +/- 5.1, respectively. The Army and Marine Corps equations underpredicted percent BF compared to UWW, P < 0.05. Bland-Altman plots showed a lack of agreement in predicting percent BF in women 40-60 yr between equation and UWW-derived percent BF. This finding was supported by the low agreement in correctly classifying an individual as meeting or exceeding the BF standards, range 25%-57%, Cohen's kappa. The low sensitivities (range 20%-74%) and higher specificities (range 80%-98%) of the equations indicated they identified individuals who met the BF standards better than those who exceeded them. Caution must be exercised when using military prediction equations to assess compliance with military BF standards in healthy middle-aged women.