Optimizing evidence-based medicine--and therefore the care of our patients--requires a public record of both the benefits and the risks of various medical interventions. Unfortunately, available evidence is often skewed because some clinical trials are withheld from publication; only selected data are reported, and statistical techniques are often inappropriately determined following data analysis. Prospective clinical trial registration (PCTR) is the public documentation of trial protocols--today primarily on the Internet--before data analysis (and ideally before trial commencement). The primary goals of PCTR are to reduce selective reporting and improve data analysis transparency, but it may also promote trial awareness for the public and other investigators. Prospective clinical trial registration is certainly not without problems, but many have been resolved, and the remainder is relatively minor in nature and easily overcome. Multiple organizations endorse (in some cases mandate) PCTR, including prominent committees of medical editors, the World Health Organization, the World Medical Association (responsible for the Helsinki Declaration), and, more recently, the US Food and Drug Administration. Although Regional Anesthesia and Pain Medicine does not currently require registration for published articles, PCTR in this and other anesthesiology and pain journals may become mandatory within the next few years. Potential authors/investigators will therefore benefit from becoming familiar with PCTR before mandatory registration implementation, and familiarity among readers may improve interpretation and understanding of clinical research results.