Patients suffering from diseased or injured organs may be treated with transplanted organs. However, there is a severe shortage of donor organs, which is worsening yearly owing to the ageing population. Scientists in the field of regenerative medicine and tissue engineering apply the principles of cell transplantation, materials science, and bioengineering to construct biological substitutes that will restore and maintain normal function in diseased and injured tissues. This article reviews recent advances in regenerative medicine and describes applications of biological substitutes that may offer novel therapies for patients with end-stage organ failure.