In the sample of 943 preschool children aged between 4 and 7 (where the arithmetic mean is 5.72 decimal years and standard deviation .882) the assessment questionnaire was used in order to get the description of children's behavior as seen by their parents. The questionnaire contained 36 items for assessing behavior.

The aim of the research was to determine which forms of behavior characterize preschool children and how behaviors are manifested with relation to sex and the age of a child. The research shows that certain forms of manifestable behavior, such as aggressiveness, vivacity, restlessness are more often manifested in boys, while in the case of girls latent forms of behavior are more often manifested. The results achieved show that a number of behaviors, mostly externalized, change and manifest less frequently under the educational impact while growing up.

The early screening of problems related to the mental health of children, especially of those referring to the behavior and emotional problems, enables timely detection and early disorder intervention.