In recent years there has been a proliferation of pharmacoeconomic studies. Concomitant to this rise in research has been an effort to set out a basic framework for economic evaluations in the form of national guidelines. Guidelines which were developed initially for Australia and Ontario, Canada, have been adapted or are under consideration in other health care settings as diverse as Finland, Norway, Portugal and the United States. The guidelines have been developed to create a set of core principles that should be followed in pharmacoeconomic studies. One goal of the guidelines is that they have prescriptive elements on study design so that a rigorous, valid and relevant pharmacoeconomic study may be used to inform decision-making about the allocation of health care resources.