Background: N-of-1 trials have been used in medicine to generate treatment information when evidence from randomized controlled trials (RCTs) is not available or applicable. N-of-1 study design maintains the methodological safeguards provided by RCTs (blinding, randomization and controls) yet avoids the disadvantages associated with large trials, such as recruitment issues, expense and lack of acceptance among alternative medicine providers. A standardized method of reporting of N-of-1 trials, such as the Consolidated Standards of Reporting Trials (CONSORT), would greatly improve the quality and consistency of trial reports in this area. Objectives: To develop a CONSORT Extension for N-of-1 Trials (CENT). Methods: Checklist items for the CENT guidelines have been derived from three ongoing systematic reviews on N-of-1 conduct, analysis and meta-analysis. A structured process of obtaining information from a group of experts is underway to refine and finalize the CENT guidelines. Starting with a modified Delphi process, two stages of questionnaires asked participants to rate the relative importance of each suggested checklist items; each questionnaire was refined based on participant feedback from the previous version. Participants include those who are known to have interests in either RCT reporting or N-of-1 methodology (journal editors, healthcare professionals, methodologists, clinical trialists and others with expertise in the reporting of RCTs). Items included after the Delphi process will be debated and finalized during an in-person meeting of an invited group of the experts in May 2009 and will form the CENT guidelines. Results: Results will be available after the CENT meeting in May 2009. Significance: N-of-1 trials may promote evidence-based approach to therapy so that families, healthcare providers and policy makers can make informed choices. The CONSORT ‘extension’ will facilitate critical appraisal and interpretation of N-of-1 trials by providing authors with guidance on how to improve reporting.