The article presents an extension to the CONSORT (Consolidated Standards of Reporting Trials) statement for reporting randomised pilot and feasibility trials. This extension aims to improve the transparency and quality of reporting in these types of studies, which are conducted to assess the feasibility of a future definitive randomised controlled trial (RCT). The extension applies to any randomised study that is part of a larger-scale RCT, regardless of its design or terminology used by authors. It includes a 26-item checklist, a separate checklist for the abstract, a template for a CONSORT flowchart, and explanations of changes made and supporting examples. The development of this extension was motivated by the growing number of studies described as feasibility or pilot studies and the identified weaknesses in their reporting and conduct. The extension retains some original CONSORT items but adapts, removes, and adds new items to cover specific aspects relevant to pilot and feasibility trials. These include how participants were identified and consented, prespecified criteria for proceeding with the future RCT, other important unintended consequences, and ethical approval. The article emphasizes that the primary aim of pilot and feasibility trials is to assess feasibility, which differs from the primary focus of definitive RCTs, which is often effectiveness or efficacy. Therefore, the reporting should reflect this difference, with a focus on assessing feasibility rather than testing hypotheses of effectiveness or efficacy. The extension also provides guidance on the description of trial design, methods, eligibility criteria, settings, interventions, outcome measures, sample size, randomisation, and allocation concealment. Overall, the authors believe that the routine use of this extension will lead to improved reporting quality in pilot trials, enabling better conduct and more reliable results for future definitive RCTs.The article presents an extension to the CONSORT (Consolidated Standards of Reporting Trials) statement for reporting randomised pilot and feasibility trials. This extension aims to improve the transparency and quality of reporting in these types of studies, which are conducted to assess the feasibility of a future definitive randomised controlled trial (RCT). The extension applies to any randomised study that is part of a larger-scale RCT, regardless of its design or terminology used by authors. It includes a 26-item checklist, a separate checklist for the abstract, a template for a CONSORT flowchart, and explanations of changes made and supporting examples. The development of this extension was motivated by the growing number of studies described as feasibility or pilot studies and the identified weaknesses in their reporting and conduct. The extension retains some original CONSORT items but adapts, removes, and adds new items to cover specific aspects relevant to pilot and feasibility trials. These include how participants were identified and consented, prespecified criteria for proceeding with the future RCT, other important unintended consequences, and ethical approval. The article emphasizes that the primary aim of pilot and feasibility trials is to assess feasibility, which differs from the primary focus of definitive RCTs, which is often effectiveness or efficacy. Therefore, the reporting should reflect this difference, with a focus on assessing feasibility rather than testing hypotheses of effectiveness or efficacy. The extension also provides guidance on the description of trial design, methods, eligibility criteria, settings, interventions, outcome measures, sample size, randomisation, and allocation concealment. Overall, the authors believe that the routine use of this extension will lead to improved reporting quality in pilot trials, enabling better conduct and more reliable results for future definitive RCTs.