The aim of the study was to investigate the correlation between motor proficiency and body mass index and to assess the socioeconomic status differences in motor proficiency and body mass index of preschool children. Sixty preschool children in the different socioeconomic status areas of central Denizli in Turkey participated in the study. The Bruininks-Oseretsky Test of Motor Proficiency, Second Edition (BOT-2) was used to assess children's motor proficiency and height/weight measurements were taken to calculate the BMI of children. There was no significant relationship between BOT-2 scores and body mass index scores of preschool children (p>0.05). There were significant SES differences in favor of high and middle socioeconomic status preschool children (p<0.05). Low socioeconomic status children had lower manual coordination, body coordination, strength and agility and total BOT-2 composite scores than their high and middle counterparts. The teachers, parents or those responsible for low socioeconomic status children in particular, have to find a way of practicing and improving the fundamental motor skills of preschool children.