This study, Creative Behavior Observation Form was developed to assess creativity of the children. While the study group on the reliability and validity of Creative Behavior Observation Form was being developed, 257 children in total who were at the ages of 5-6 were used as samples with stratified sampling method. Content Validity Index (CVI) and Confirmatory Factor Analysis (CFA) were applied in order to measure validity of Creative Behavior Observation Form. Test-retest method was used in order to determine if Creative Behavior Observation Form has reliable measurements in time. This study concludes with recommendations for the applicators, researchers and teachers who will use Creative Behavior Observation Form as an instrument to develop creativity of preschool children. [This study has been presented as an oral representation paper at the 2nd International Conference on Lifelong Education and Leadership in Latvia, 21-23 July, 2016.]