Background and aims Overweight and obesity among children became an important public health concern as their prevalence within the preschool population has been markedly increased in last decades. The aim of the present study was to examine and compare the prevalence of overweight and obesity among 5–6 year old children either sex in year 2003 and year 2013.

Methods Overweight and obesity were measured by body mass index (BMI). BMI 85–95th percentile was considered as overweight and BMI ≥ 95th percentile represents obesity. The study was performed in the total population of 859 nonselected 5–6 year old children (423 in 2003 and 436 in 2013) by retrospective analysis of their medical documentations.

Results The overall prevalence of overweight in 2003 was 9.63%, whereas the prevalence of obesity was 9.46%. However, 10 years later, in 2013, the prevalence of overweight was significantly higher (15.6%) as well as the prevalence of obesity (13.53%). Prevalence of overweight and obesity among preschool children is significantly increased in the last decade (student t-test, p).

Conclusions Data from 2013 indicate that about 30% of young children encounter the obesity problem. Therefore, children at this age already should represent the priority population for intervention strategies such as control of diet and/or physical activity.