The research community has embraced trial registration. Before the ICMJE policy, ClinicalTrials.gov, the largest trial registry at the time, contained 13 153 trials; this number climbed to 22 714 one month after the policy went into effect (3). In April 2007, the registry contained over 40 000 trials, with more than 200 new trial registrations occurring weekly (Zarin D. Personal communication). The 4 other registries that meet the ICMJE criteria have also grown as scores of journals have adopted the ICMJE clinical trials registration policy. In response to burgeoning registration, many investigators, sponsors, and government agencies have asked the ICMJE to recognize their local registries as databases that meet the policy. Fortunately, the World Health Organization's (WHO) International Clinical Trial Registry Platform (ICTRP), which was nascent when the ICMJE began to require trial registration, has matured rapidly and provides options for those that desire a wider array of registries. The ICTRP has taken the first steps toward developing a network of primary and partner registers that meet WHO-specified criteria (4). Primary registers are WHO-selected registers managed by not-for-profit entities that will accept registrations for any interventional trials, delete duplicate entries from their own register, and provide data directly to the WHO. Partner registers, which will be more numerous, will include registers that submit data to primary registers but limit their own register to trials in a restricted area (such as a specific disease, company, academic institution, or geographic region).