The aim of this study was to examine the validity of the Bruininks-Oseretsky Test of Motor Proficiency – Short Form (BOTMP-SF) (Bruininks, 1978) for the assessment of preschool aged children. Three hundred and eighteen children 48-71 months old (M = 58.97 months, SD = 6.73) participated in the study. For the data analysis both an ANOVA and a MANOVA were applied with the total battery score and the 14 item scores being the dependent variables, respectively. Age was found to have a significant effect on both children's total battery score ((3, 314) = 110.65, < .001, η = .68) and 13 item scores (minimum (3, 314) = 8.75, < .001, minimum η = .145). Although the aforementioned results represent an evidence for the validity of the BOTMP-SF, a closer study on the score of each item revealed a high percentage of zero scores on four items. Task difficulty has caused a floor effect, constituting a threat to the validity of the preschoolers' motor assessment with the above battery. A modification of the battery items is suggested, so that the BOTMP-SF will give valid results for children 4-6 years old.