Disturbingly, one in four people suffer complications after surgery. Death within 30 days after surgery is the 3rd leading cause of death worldwide (after death from ischaemic heart disease and death from stroke). Even mild complications, such as postoperative lung complications (occurring in one in three patients), associate with increased postoperative death. Aside from increasing mortality, postoperative complications also increase hospital length of stay, re-admission rates, increased healthcare expenditure, and delay the timely return to adjuvant therapy for cancer patients to impact their cancer survival. It is increasingly recognised that unchecked modifiable preoperative risk (e.g., deconditioning from poor fitness [functional capacity], malnutrition, etc.) is a key driver of postoperative complications. The physiological challenge of major surgery is likened to running a marathon—in both cases, preparation is critical. Yet, many patients with cancer embark on major cancer surgery in a deconditioned state. Prehabilitation allows preparation for major surgery by improving the physiologic capacity of patients to withstand the stressor of major surgery. Prehabilitation is delivered as a multimodal intervention bundle tailored to the individual and focuses on patient education, exercise, nutrition and psychological support provided before surgery. The benefits of prehabilitation are promising, albeit within the limitations of small RCTs, with a significant reduction in complications after general abdominal surgery. Current recommendations are to risk stratify patients and to provide stepped, individualised interventions based on the level of risk assessment, with the therapy delivered as universal (all patients), targeted or specialist prehabilitation.