Falls among older people are common and are associated with substantial morbidity, mortality and healthcare costs. Increasingly cancer is becoming a disease of older people and fall rates are higher in elders living with cancer. Cancer and its treatments potentiate important risk factors for falls, including muscle weakness, poor balance, proprioception, cognitive impairment and functional disability. Sarcopenia refers to the progressive deterioration in muscle strength, mass and quality with ageing. Chronic conditions and cancer amplify this decline and are associated with a greater negative effect on function. Age-related impairments of lower limb neurological function are commonly exacerbated by neurotoxic chemotherapy, resulting in gait and balance deficits. Postural instability and falls erode confidence and result in a negative cycle of diminishing activity levels, further deconditioning and a higher risk of further falls. Cancer-related fatigue, sleep and mood disturbances compound this progressive frailty, further worsening treatment tolerance and outcomes. Cognitive impairment is a potent risk factor for falling and is frequently associated with gait abnormalities. The well-recognised effects of cancer treatment on working memory, attention, processing speed and executive function are often apparent (when their presence is sought) before treatment and may be as much the result of the cancer itself as they are ‘chemo brain'. Structured exercise programmes focusing on progressively challenging strength and balance training are of proven benefit in falls prevention. Regular aerobic exercise accrues additional benefits in improved cardiorespiratory resilience and concomitant positive effects on treatment tolerance. Increased activity levels positively influence cognition, mood and foster an improved sense of well-being. Simple, practicable clinic-based tests of physical functioning, cognition and neurological function can help to identify those at high risk of falls and functional decline. The use of such instruments can aid judicious treatment planning and identify those most likely to benefit from more detailed specialist comprehensive geriatric assessment.