Purpose: This study compared the hand function of children between the ages of 8 and 12 years with type 1 diabetes mellitus (T1DM) with that of children without diabetes. Methods: The Modified Jebsen-Taylor Hand Function Test and the Purdue Pegboard Test were used to assess hand function. The Pediatric Quality of Life Inventory 4.0 was used for evaluating health-related quality of life. Results: Duration of writing was found to be significantly longer on the dominant side of the T1DM group compared with the children without T1DM. The durations of card turning, moving large, light objects, and large, heavy objects on the nondominant side of the T1DM group were also found to be significantly longer than those in the children without T1DM. The total scale score of health-related quality of life was significantly lower in the T1DM group compared with the children without T1DM. Conclusions: T1DM affects hand function, particularly the dominant side for writing and nondominant side for card turning and moving large objects.