The goal of this study was to examine the differences in prosociality andaggressiveness of typically developed children, considering gender, age, number ofchildren in educational groups and integrative group affiliation. Also, the goal of thisstudy was to examine the relationship between the parent and teacher attitudes towardintegration of children with dissabilities in regular classroom setting with prosociality andaggressiveness of typically developed children in integrative groups. The study included257 typically developed children of preschool age, of which 122 attending integrativegroups, and 133 children in regular groups, along with 108 parents of typically developedchildren in integrative groups and 33 teachers. Teachers evaluated prosocial andaggressive behavior of children on Scale for evaluation of prosocial and aggressivebehavior. The attitudes of parents and teachers were examined on Opinions relative tomainstreaming scale. The analysis of variance confirmed gender and age differences inprosociality, along with the effect of group size. Thus, girls act more prosocialy, comparedto boys. Also, older children act more prosocialy, compared to younger children. Childrenin smaller groups are more prosocial compared to children in larger groups. The effect ofintegrative setting has been confirmed in interaction with age and group size. Youngerchildren in integrative settings are less prosocial than younger children in regular settings,while the older children in integrative settings act more prosocialy compared to olderchildren in regular settings. Children in smaller regular goups tend to be more prosocialthan children in larger regular groups, while there is no difference in integrative groups.Analysis of variance confirmed gender differences in aggressiveness of typically developedchildren. Specifically, boys are more aggresssive than girls. Hierarhical regressionanalysis identified a significant contribution of parents attitudeds towards integration inexplaining boys aggressive behavior. Boys whose parents have more positive attitudes tendto be more prosocial, compared to boys whose parents have less positive attitudes towardintegration.