The aim of this study was to evaluate sequential hypothermic and normothermic machine perfusion (NMP) as a tool to resuscitate and assess viability of initially declined donor livers to enable safe transplantation. Machine perfusion is increasingly used to resuscitate and test the function of donor livers. Although (dual) hypothermic oxygenated machine perfusion (DHOPE) resuscitates livers after cold storage, NMP enables assessment of hepatobiliary function. In a prospective clinical trial, nationwide declined livers were subjected to ex situ NMP (viability assessment phase), preceded by 1-hour DHOPE (resuscitation phase) and 1 hour of controlled oxygenated rewarming (COR), using a perfusion fluid containing an hemoglobin-based oxygen carrier. During the first 2.5 hours of NMP, hepatobiliary viability was assessed, using predefined criteria: perfusate lactate <1.7 mmol/L, pH 7.35 to 7.45, bile production >10 mL, and bile pH >7.45. Livers meeting all criteria were accepted for transplantation. Primary endpoint was 3-month graft survival. Sixteen livers underwent DHOPE-COR-NMP. All livers were from donors after circulatory death, with median age of 63 (range 42-82) years and median Eurotransplant donor risk index of 2.82. During NMP, all livers cleared lactate and produced sufficient bile volume, but in 5 livers bile pH remained <7.45. The 11 (69%) livers that met all viability criteria were successfully transplanted, with 100% patient and graft survival at 3 and 6 months. Introduction of DHOPE-COR-NMP increased the number of deceased donor liver transplants by 20%. Sequential DHOPE-COR-NMP enabled resuscitation and safe selection of initially declined high-risk donor livers, thereby increasing the number of transplantable livers by 20%. www.trialregister.nl; NTR5972.