With the aim of measuring preschool children temperament, EASI temperament Survey has been applied. Preschool teachers (N = 192), all female, rated a total of N = 3275 children (1612 girls and 1639 boys) with mean age M 4.368 (SD = 1.482) within age range between 7 months and 7.7 years. Validation for the instrument was run. Factor analysis on principal components with Oblimin rotation and reliability analysis were performed on data based on preschool teachers' ratings. Three-factor solution has been determined: Emotionality, Activity and Sociability, which have explained 57.427% variance. As it was expected, impulsivity component was not replicated. Subscales inter-correlations and gender and age differences confirmed results from prior research. Overall, the findings were discussed within the frame of preschool children temperament development and variables related to the characteristics of observers. Several significant implications for preschool teachers practice and the quality of educational process have been emphasized.