In Brazil, Resolution 196/96 on research involving human subjects created the National Council of Ethics in Research (CONEP) with a mandate to stimulate the creation of institutional review boards (IRBs) throughout the country, provide guidelines, and regulate their structure and operation. A descriptive study was carried out in 2007. The coordinators of all 508 IRBs registered in CONEP in 2006 were invited to participate; 502 accepted (response rate = 99%) and responded to a structured questionnaire conducted via telephone. Prior to the publication of Resolution 196/96, IRBs were created at an average rate of 1.7 per year. In contrast, an average of 47.3 IRBs per year were created between 1997 and 2006. The percentage of IRBs with their own physical space and telecommunication equipment was higher among older IRBs compared to more recently established IRBs. A significantly greater proportion of IRBs created prior to the year 2000 provided services for other institutions, offered courses, and produced texts on bioethics compared to the more recently established IRBs. Thus, in a period of only 12 years, Brazil progressed from having a small number of functioning IRBs to the current number of 508, reflecting the capacity of the federal government to mobilize teaching and research institutions and investigators. Nevertheless, while research institutions are adhering to the requirement for the social control of ethics in research, they are not yet willing to provide the resources these committees need to function properly. Despite these limitations, the colossal effort to promote implementation of appropriate ethical standards in research studies involving human subjects in Brazil has been successful.