This paper is concerned with the problem of giving a correct analysis of function statements as they are used in biology. Examples of such statements are (1) The function of the myelin sheath is to insulate the nerve fiber and (2) The function of chlorophyll is to enable photosynthesis to take place. After criticizing analyses of such statements developed by Braithwaite, Nagel and Hempel an analysis is presented by the author. Finally the question of whether function statements are explanations is (...) discussed briefly. (shrink)