The spread of privatization in almost every country over the last decade reflects a rapid and fundamental change in patterns of policy instrument usage. Yet the literature on policy instruments has almost nothing to say on this perhaps most significant development in public policy in recent times. This paper's objective is to aid in the development of a theory of policy instrument choice which is capable of dealing with instances of long-term, cross-national changes in policy instrument usage. It will be argued that reconceptualization of instrument choices in terms of policy learning can aid in this theoretical project. Copyright 1993 by The Policy Studies Organization.