The purpose of this study was to compare measurements of elbow flexor muscle strength obtained with a modified sphygmomanometer (MS) and a strain gauge hand-held dynamometer (HHD). Thirty-two healthy subjects performed two isometric contractions of about five seconds against each device. Repeated measurements with each device did not differ significantly and were correlated (r greater than .960) and reliable (intraclass correlation coefficients greater than .960). The means of two measurements obtained with each device were related in a curvilinear manner (R = .882), with MS measurements above 210 mmHg rising more slowly than corresponding HHD measurements. Although supporting the reliability of each device, the results suggest that the devices do not provide comparable measurements throughout the range of the MS. The MS may not be the best choice for obtaining accurate strength measurements of stronger individuals.