The validity of ten popular anthropometric percent fat prediction equations for estimating changes in percentage of body fat for obese females was studied. Thirty-one obese females (mean ± SEM, %fat = 36.7 ± 1.1%, body mass = 75.6 ± 1.7 kg, age = 32.8 ± 1.1 years) participated in a diet-only, diet-plus-exercise, or exercise-only program. Subjects lost 2.7 ± 0.3 fat percentage points and 3.0 ± 0.3 kg body mass during the 8-week study. While many of the equations had acceptable validity before and after body mass loss, when applied to the prediction of changes in body fat none of the equations was acceptable. It was concluded that use of anthropometric prediction equations to estimate individual percent fat change scores results in large errors and is not recommended.