Background and Purpose: Illegible handwriting is one of the common problems in preschool children. Handwriting is a complex perceptual-motor skill that depends on the evolution and integration of a number of cognitive-perceptual and motor skills that can develop through training. Therefore, this study aimed to investigate the effect of training the perceptual-motor skills on the improvement of handwriting in preschool children.
Method: This research was a quasi-experimental study with control group pretest-posttest design. The population included all the 5 to 6-year old pre-school boys who had been referred to the counseling center of Education Administration in District 2 of Isfahan city in the academic year 2017-2018. They were screened by Handwriting Problems Checklist (Keshavarzi& Shojaee, 2015). A sample of 20 children with handwriting problems was selected by convenience sampling and then randomly placed in the experimental or control group (10 per group). The experimental group received the cognitive-movement skills training program for sixteen 45-min sessions but the control group received no training. Then, both groups completed the posttest. The measurement tool in this research was Handwriting Problems Checklist (Keshavarzi& Shojaee, 2015). For data analysis, uni-variate analysis of variance and multivariate analysis of variance were used.
Results: Data analysis showed that cognitive-motor skills training program was effective on the improvement of handwriting problems (F = 14.73, P = 0.001) and on the subscales of handwriting errors (F = 12.40, P = 0.002) and body condition error at the time of writing (F = 6.12, P = 0.024) in the 4 to 6-year old pre-school boys.  
Conclusion: Based on the results, it can be concluded that cognitive-motor skills training was effective on the improvement of handwriting skills through strengthening the hand muscles and reinforcing the gross and fine motor skills. As a result, this method can be used as a supplementary treatment along with other therapies available for this problem.