Loss of grip is a rateable factor in the determination of permanent disability by compensation boards in some states. Malingerers, or those with psychological rather than organic disability, can voluntarily record lower grip measurements in the so-called injured hand when compared with the normal hand. The purpose here is to provide on objective method of documenting real, as opposed to fictitious, loss of grip. This method utilizes the sealed hydraulic dynamometer which has been adopted by some states as a standard grip measuring device. Its isometric and adjustable features have been utilized in this study to aid in the evaluation of the patient who complains of loss of grip with no objective recordable findings. The patient who is voluntarily attempting to demonstrate weakness of grip will apply the same minimal pressure at each of the adjustable handle positions, producing a straight line graph. In our series of patients thought to be voluntarily applying minimal grip, there has been a variance of 5 lb, or less at each of the handle positions. An objective statement can then be made that the patient did not cooperate with the test through his failure to apply maximal pressure at each dynamometer handle position as instructed.