We aim to provide evidence-based clinical practice guidelines for the use of VV ECMO in adult patients across Australia and New Zealand. Developed by a multidisciplinary panel of clinicians from both countries, alongside a methodologist and patient representatives, these guidelines were produced in accordance with the National Health and Medical Research Council (NHMRC) 2016 standards for guidelines. The GRADE (Grading of Recommendations, Assessment, Development and Evaluation) approach was used to assess the certainty of evidence and inform the development of recommendations. These guidelines are intended to support, not replace, clinical judgement and should be applied in the context of individual patient circumstances, values and preferences. In this part one of a three-part series, the Guideline Development Group (GDG) addressed four core clinical questions regarding the indications for and management of VV ECMO in adults. In addition to evidence-based recommendations, this guideline incorporates expert consensus through a well-established process and highlights important gaps in current evidence to guide future research priorities.