The CONSORT 2010 statement has been extended to include randomised pilot and feasibility trials conducted before a future definitive RCT. This extension applies to any randomised study where a future definitive RCT or part of it is conducted on a smaller scale, regardless of design or terminology. The extension does not apply to internal pilot studies, non-randomised pilot and feasibility studies, or phase II studies, but these studies share similarities with randomised pilot and feasibility studies, so many principles may apply. The extension was developed to address the growing number of studies described as feasibility or pilot studies and to improve their reporting and conduct. It was developed following good practice, including a Delphi survey, consensus meeting, and pilot testing of the checklist. The aims and objectives of pilot and feasibility randomised studies differ from those of other randomised trials, so while much of the information to be reported is similar to RCTs assessing effectiveness and efficacy, there are key differences in the type of information and interpretation of standard CONSORT items. The extension retains some original CONSORT items but adapts, removes, and adds new ones. New items cover participant identification and consent, prespecified criteria for proceeding with a future RCT, unintended consequences, implications for progression, and ethical approval. The article includes a 26-item checklist, a separate checklist for the abstract, a CONSORT flowchart template, and an explanation of changes and examples. The CONSORT statement is a guideline to improve the transparency and quality of reporting of randomised trials. It was first published in 1996, revised in 2001, and last updated in 2010. It comprises a checklist of essential items and a diagram of participant flow. The CONSORT statement has received international recognition and has been cited over 8000 times. Extensions to the CONSORT checklist for non-inferiority, equivalence, cluster, and pragmatic designs, as well as for harms, different interventions, and patient-reported outcomes, have been published. The extension applies to randomised pilot and feasibility trials conducted before a future definitive RCT. These trials aim to assess the feasibility of conducting the future RCT. The extension does not apply to internal pilot studies or non-randomised pilot and feasibility studies, but much of what is presented may apply to these types of studies. Pilot trials often focus on assessing feasibility rather than effectiveness or efficacy, and may use surrogate outcomes to assess potential effectiveness. The extension was developed through a process involving defining pilot and feasibility studies, reviewing existing CONSORT items, and conducting a Delphi survey to reach consensus on checklist items. The final checklist includes 26 items, with explanations and examples. The extension aims to improve the reporting of pilot trials, enabling better conduct and use of results in future trials.The CONSORT 2010 statement has been extended to include randomised pilot and feasibility trials conducted before a future definitive RCT. This extension applies to any randomised study where a future definitive RCT or part of it is conducted on a smaller scale, regardless of design or terminology. The extension does not apply to internal pilot studies, non-randomised pilot and feasibility studies, or phase II studies, but these studies share similarities with randomised pilot and feasibility studies, so many principles may apply. The extension was developed to address the growing number of studies described as feasibility or pilot studies and to improve their reporting and conduct. It was developed following good practice, including a Delphi survey, consensus meeting, and pilot testing of the checklist. The aims and objectives of pilot and feasibility randomised studies differ from those of other randomised trials, so while much of the information to be reported is similar to RCTs assessing effectiveness and efficacy, there are key differences in the type of information and interpretation of standard CONSORT items. The extension retains some original CONSORT items but adapts, removes, and adds new ones. New items cover participant identification and consent, prespecified criteria for proceeding with a future RCT, unintended consequences, implications for progression, and ethical approval. The article includes a 26-item checklist, a separate checklist for the abstract, a CONSORT flowchart template, and an explanation of changes and examples. The CONSORT statement is a guideline to improve the transparency and quality of reporting of randomised trials. It was first published in 1996, revised in 2001, and last updated in 2010. It comprises a checklist of essential items and a diagram of participant flow. The CONSORT statement has received international recognition and has been cited over 8000 times. Extensions to the CONSORT checklist for non-inferiority, equivalence, cluster, and pragmatic designs, as well as for harms, different interventions, and patient-reported outcomes, have been published. The extension applies to randomised pilot and feasibility trials conducted before a future definitive RCT. These trials aim to assess the feasibility of conducting the future RCT. The extension does not apply to internal pilot studies or non-randomised pilot and feasibility studies, but much of what is presented may apply to these types of studies. Pilot trials often focus on assessing feasibility rather than effectiveness or efficacy, and may use surrogate outcomes to assess potential effectiveness. The extension was developed through a process involving defining pilot and feasibility studies, reviewing existing CONSORT items, and conducting a Delphi survey to reach consensus on checklist items. The final checklist includes 26 items, with explanations and examples. The extension aims to improve the reporting of pilot trials, enabling better conduct and use of results in future trials.