Dendroclimatology is a science which is used in finding out the relationships between tree-rings and elimate and in reconstructing the past climate. Several method s have been developed to investigate the relationships between especially monthly temperatures and precipitation with tree-rings. The aim of this article is to explain the response function, which is preferred mueh more than other methods, and to help to dendroelimatologists in using the method. Response function is caleulated in two stages whieh are principle component analysis and multiple regression, respeetively. In this article, the response funcıion is explained in detai!.