The purpose of this study was to develop the “observational scheme of child’s free play in kindergarten” (OFP) and examine the associations between “child’s attachment to his/her kindergarten teacher” (CAKT) and: (1) cognitive and social play behaviour, (2) child’s contacts with his/her peers and teacher during free play session in kindergarten, and (3) child’s personality characteristics. One hundred and one children (57.4% male) participated in the research. Children’s ages ranged from 24 to 74 months (M = 51.4; SD = 12.0). Trained observers filled in the OFP, CAKT and the “inventory of child individual differences” (ICID). Play behaviour was observed at kindergarten during free play sessions of 60 minutes, and cognitive and social play categories were coded. Metric characteristics of the OFP appeared to be satisfactory. Results revealed significant correlations between children’s secure and resistance attachment to their kindergarten teachers and cooperative play, the contacts with their peers and teachers during free play session in kindergarten and their personality characteristics. In future, it will be necessary to analyse the causational associations between discovered variables. (Contains 9 tables.)