The time required to approve new drugs in Canada is significantly longer than that in Sweden, the United Kingdom and the United States. The timeliness with which a regulatory agency approves drugs may be influenced by the human resources available to review applications. Therefore, the number of full-time equivalent (FTE) staff members who evaluate and approve new drug applications was sought directly from the regulatory agencies of Canada, Australia, Sweden, the United Kingdom and the United States. Information was received from the Therapeutic Products Directorate (TPD) of Health Canada, the Swedish Medical Products Agency (MPA), the United Kingdom Medicines Control Agency (MCA) and the United States Food and Drug Administration (FDA). The Australian Therapeutic Goods Administration (TGA) did not provide data, but the Australian Pharmaceutical Manufacturers Association estimated the number of personnel reviewing drug applications at the TGA to be 102. After adjustment to eliminate staff members whose primary responsibility is reviewing generic applications, there were an estimated 159 FTE staff members at the TPD, 1610 at the FDA, an estimated 76 at the TGA, 60 at the MCA and 46 at the MPA. Thus, the number of personnel in Canada is two to 3.5 times that in Australia, the United Kingdom and Sweden, but less than 10% of that in the United States. Because Sweden, the United Kingdom and the United States all have significantly shorter review and approval times than Australia and Canada, the number of review staff does not appear to be a direct major determinant of the timeliness of an agency's review and approval performance.