Higher levels of physical activity pre- and post-diagnosis of cancer have been associated with improved survival post-cancer. However, evidence to date does not demonstrate cause and effect. Consequently, trial evidence is now needed to demonstrate the effect of exercise on survival in a clinical setting. The Exercise during Chemotherapy for Ovarian cancer (ECHO) trial is a phase III, randomised, controlled trial, designed to determine the effect of exercise on progression-free survival and physical wellbeing for patients receiving first-line chemotherapy for ovarian cancer. Women with newly diagnosed primary ovarian cancer, scheduled to receive first-line chemotherapy are eligible to participate in ECHO (target sample size; n=500). Following consent, women are randomly allocated (1:1), with stratification for recruitment site, age, stage of disease and chemotherapy delivery (neoadjuvant versus adjuvant) to either the Exercise Intervention (plus Usual Care) or Usual Care alone. The exercise intervention involves individualised exercise prescription with a weekly target of 450 metabolic equivalent minutes per week (that is, at least 150 minutes of moderate-intensity, mixed-mode exercise), delivered to participants via weekly telephone sessions with a trial-trained exercise professional for the duration of first-line chemotherapy. Outcomes of interest include progression-free survival and physical wellbeing (primary outcomes), and overall survival, physical function, body composition, quality-of-life, fatigue, sleep, lymphoedema, anxiety, depression, chemotherapy completion rate, chemotherapy-related adverse events, physical activity levels and healthcare usage. Throughout this presentation, the rationale supporting the study design and characteristics will be provided and preliminary findings related to exercise safety and feasibility will be described. The target sample size will be met by December, 2022, and therefore results related to the primary and secondary research questions will become available within the next few years.