This study was designed to determine the validity of measuring grip strength in functional upper extremity positions. A dynamometer was used to measure the grip strength of 90 subjects(24 female and 66 male) in three positions: (1 ) standard position with elbow in 90°flexion, (2) elbow in full extension, and (3) functional position of the upper extremity. The three positions were randomized and standardized instructions were followed. One way repeated ANOVA and averaged univariate results were used to determine any significant difference in grip strength between three the positions. The ANOVA results revealed a significant F-ratio for all three positions. The averaged univariate results revealed that there was no significant difference between the standard and functional positions. Thus, when assessing grip strength clinically, we can use either the standard or the functional upper extremity position.