The concept of school readiness, and its most important aspect-the intellectual school readiness are defined. School readiness without any doubt is a complex concept, and its specific attributes are interrelated and constitute a single dialectical whole. Factors determining school readines are discussed. Five collective non-verbal school readiness tests standardized on 1919 children aged 6 to 6,5 have been devised for estimation of the intellectual school readiness in children entering school. Analysis of the data obtained in application of the tests, from different viewpoints and on the basis of different statistics, is presented.