[Purpose] The purpose of this study was to examine the effect that fine motor skills have on handwriting legibility in children of preschool age. [Subjects and Methods] The subjects of this study were 52 children of normal growth and development. In order to ascertain handwriting legibility, a Korean alphabet writing assessment was used; to measure fine motor skills, fine motor precision and manual dexterity, sub-items of BOT-2 were measured. Furthermore, in order to measure in-hand manipulation skills, a Functional Dexterity Test was conducted. [Results] The results of the study showed a high level of correlation between fine motor skills and handwriting legibility. The study revealed that the accuracy of hand and in-hand manipulation skills is factors that have an effect on handwriting legibility. [Conclusion] Through the current research, occupational therapists can provide activities that aid the development of fine motor precision and in-hand manipulation skills for children during the instruction and treatment of handwriting to preschool age children, which helps to conduct better legibility in their handwriting.