SummaryAn attachment was designed which made it possible to use the Allo-Kramer shear press to determine the breaking strength of the tibia of 4-week old chicks. Breaking strength determined in this manner was found to be highly correlated with tibia ash. It is suggested that the breaking strength is as good a measure of dietary calcium and phosphorus levels as is tibia ash. Also the breaking strength of bones as determined in this manner may be useful in evaluating factors influencing fragility of bones.