Older patients, particularly if debilitated, deserve special thought when prescribing. With a rapidly ageing population, every clinician must be comfortable prescribing for this unique set of patients. While it is important to consider frailty, cognitive impairment and declining organ function, clinicians must also beware of physical barriers to drug adherence, the hazardous effects of polypharmacy and of the importance of shared decision-making when making treatment decisions. These complex issues and others are discussed in this chapter.