The purpose of this study was to determine what differences exist in the content of commercial drug compendium monographs available in First World and Third World countries. A content model representing First World information was developed from monographs contained in the Physicians' Desk Reference, ABPI Data Sheet Compendium, and the Rote Liste. The content of the three First World compendia was found to be variable, with the Physicians' Desk Reference consistently more comprehensive than either the ABPI or Rote Liste. This result suggests that there is a lack of agreement among industrialized countries regarding what amount of information is necessary or appropriate for inclusion in a commercial drug compendium. A sample of 58 monographs was selected from four Third World compendia and evaluated in terms of comprehensiveness and accuracy. These monographs represented five commonly prescribed drugs from the World Health Organization's Essential Drugs List. The monographs were found to be less comprehensive than any of the three monographs contained in the First World compendia. Approximately 5 percent of the information contained in the sampled monographs was determined to be inaccurate. The sampled monographs for drugs supplied by multi-national pharmaceutical firms were found to contain the same amount of information as those for drugs supplied by domestic firms.