Aim The aim of our study was to assess all aspects of school readiness (cognitive, personal–social, growth, language, etc) in children aged 5–6 years. The cross-sectional study was conducted in randomly selected kindergartens and households to compare school readiness in organised and non-organised children. We studied 438 5–6-year-old children (268 organised and 170 in households), 228 girls and 210 boys. School readiness was assessed by the special tests that include nine subtests to assess logical ability, orientation and mathematical ability, language, pictures from Wexler tests, geometric figures, classification, drawing a person (Goodenough–Harris). At the same time we assessed body mass index (BMI).

Results Low scores of school readiness were found in 15% of girls and 20% of boys, the highest score was 35.3% and 17%. The school readiness scores in girls were significantly (p<0.005) higher than in boys. The scores were significantly (p<0.005) higher in children who attended kindergarten. There was no significant correlation between BMI and school readiness scores.

Conclusion Clinicians should know how to assess school readiness and make appropriate recommendations for interventions when problems are identified. Timely intervention for cognitive, emotional, or social difficulties can have a positive effect on a child’s attitude towards school and learning.