The purpose of my study is to highlight the importance of play for children's social development in preschool. The study is based on active preschool teachers' perceptions and personal experience on the importance of play for children's social development. What are their own thoughts about children who rarely play and how you react as a teacher to the children who rarely plays with other children? The study is based on qualitative interviews with five preschool teachers who work in different sections in preschools. I chose to use my interviews to illuminate the preschool teachers' own view and experiences out of children's play and how it may affect the child's social development. The results of my interviews showed that preschool teachers agree that play is an important part of children's social development and that it is in the game, children can develop their imagination, motor skills and interaction with other children. In the game and the interaction with other children they observes first one another and imitate what other children are doing before there is time for the children themselves to laugh and play together. The results also showed that it is important that a preschool teacher is included in the children's play, not always active but present in the room where the children themselves play. It is also important that the child feel secure in being at the preschool in order to play and that as a preschool teacher is a guide for the children who rarely play together with other children to help them into the other children´s play.