Methods for appropriate costing in Cost-effectiveness analyses (CEAs), seemingly straightforward, have always raised questions. Questions linger about what cost components to include under a "societal" perspective, as well as how to value resources.This article discusses issues surrounding costing and "perspective" in published CEA.I examine data from the Tufts Medical Center Cost-Effectiveness (CEA) Registry to investigate the use of perspective and costing methodology in published cost-utility analyses. The CEA Registry contains over 3000 cost-utility ratios and utility weights for roughly 4000 health states from 1164 published cost-utility analyses through 2005. The Registry also provides an online-based searchable database (Available at: www.cearegistry.org). I analyze changes over time in several dimensions related to costing methodology: disclosure of study perspective; statement of time horizon; use of discounting for future costs and quality-adjusted life years (QALYs); statement of year of currency; reporting of sensitivity analysis; and use of incremental analysis.In practice, there has been a great deal of variation in costing methodology used in published CEAs, though methods have improved somewhat over time. Many CE researchers continue to claim that their studies take a societal perspective, but instead their articles only consider a health care payer perspective.Analysts conducting CEAs should be more transparent about their costing methodology and clearer in their usage of terminology regarding perspective. The field would also benefit from more attention to the question of how much different costing methods influence the results of CEAs.