Objective. The purpose of this study was to establish normative data on spherical grip strength of children 3 to 6 years of age with the Martin Vigorimeter. Method. Two hundred twenty-five preschoolers in the Kalamazoo, Michigan, area were tested with standardized positioning and instructions. The mean of three trials for each hand was used as the grip-strength score. A repeated measure design was used and the right and left hands were alternated during testing to allow a 20-sec rest period between trials. Hand width also was measured in inches from the head of the second metacarpal to the head of the fifth metacarpal. Results. Hand width and grip strength were significantly correlated for both the right (p < .0001) and the left hands (p < .001). Grip strength increased linearly across all of the age groups (p < .001). The results of paired t tests did not show a significant difference in grip strength between the right and left hands or between boys and girls. A table of mean grip-strength scores and hand width measurements along with their standard deviations is presented for clinical use. Conclusion. The vigorimeter could be used to assess the grip strength of children with rheumatic disorders without putting excessive pressure on the joints or skin of the hand.