Obesity, physical inactivity and poor diet quality have been associated with increased risk of breast cancer-specific and all-cause mortality as well as treatment-related side-effects in breast cancer survivors. Weight loss intervention trials in breast cancer survivors have shown that weight loss is safe and achievable; however, few studies have examined the benefits of such interventions on a broad range of outcomes and few have examined factors important to translation (e.g. feasible delivery method for scaling up, assessment of sustained changes, cost-effectiveness). The Living Well after Breast Cancer randomized controlled trial evaluated a 12-month telephone-delivered weight loss intervention (versus usual care) on weight change, a range of secondary outcomes and cost-effectiveness. Women (18-75 years; BMI 25-45 kg/m2) diagnosed with stage I-III breast cancer in the previous two years were recruited from public and private hospitals and through the state-based cancer registry (target n=156). Following baseline assessment, participants were randomized to either a 12-month telephone-delivered weight loss intervention (targeting diet and physical activity) or usual care. Data were collected at baseline, 6-months, 12-months and 18-months. Weight change at 12-months was the primary outcome. Secondary outcomes were changes in body composition, bone mineral density, cardio-metabolic and cancer-related biomarkers, metabolic health and chronic disease risk, physical function, patient-reported outcomes and behaviours. Data collected at 18-months will assess whether outcomes achieved at end-of-intervention are sustained six months after intervention completion. In total, 159 participants were recruited: (mean±SD) 55±9 years, 31.3±4.0 kg/m2, 10.7±5.0 months post-diagnosis and 45.5% with metabolic syndrome. Study retention was 89.3% at 6-months, 81.8%% at 12-months and 79.9% at 18-months. This presentation will discuss preliminary findings on secondary outcomes. Findings from this trial will add to the evidence needed to inform the wide-scale provision of weight loss, physical activity and dietary interventions as part of routine survivorship care for breast cancer survivors.