The purpose of the study was to check the calibrations of six Jamar dynamometers. Five handle positions were tested for each instrument, with the application of seven different external forces, from 5 kg to 60 kg. Between two testers the repeatability was also evaluated. Major differences in testing accuracies were not found according to different breadths of grip. The repeatability of testing accuracy among the two examiners was rather good, varying in average from only 1.2 kg to 1.4 kg per handle position. The error of absolute kilograms increased relating to heavier loads, but the percentage error decreased when the load increased. The accuracy of the older dynamometers was poorer than the accuracy of the newer ones. The normative values of hand grip related to different handle positions are reviewed.