The ability to read and write is essential to be able to live and function as an adult in today’s information and knowledge intensive society. Both public libraries and preschools have a duty to promote reading to children, but how their reading promotional activites are carried out varies. In the autumn of 2016 84 percent of all children in Sweden aged between one and five attended preschool and through collaborations between public libraries and preschools reading can be promoted to the majority of Swedish children. The aim of this study is to map how public libraries and preschools work together with reading promotion and how they view future collaborations, as well as to investigate what organisational factors that affect these partnerships. Surveys have been sent out to all main public libraries in Sweden’s 290 municipalities, and 215 completed surveys have been returned. The results shows that there is a significant amount of collaborations between public libraries and preschools in reading promotional purposes and that the public libraries use several approaches for these activities. The results also show that organisational factors such as financial circumstances and policies are of a big significance and that they affect these partnerships. It is possible to see a great interest amongst the public libraries for collaborations with preschools for reading promotional purposes, both now and in the future. Public libraries and preschools have similar missions regarding the promotion of reading, and this means that there is an opportunity for increased collaborations in the future.