Prescribing in care homes for older people has been the focus of much research and debate because of inappropriate drug choice and poor monitoring practices. In the US, this has led to the implementation of punitive and adversarial regulation that has sought to improve the quality of prescribing in this healthcare setting. This approach is unique to the US and has not been replicated elsewhere. The literature has revealed that there are limitations as to how much can be achieved with regulation that is externally imposed (an 'external factor'). Other influences, which may be categorised as 'internal factors' operating within the care home (e.g. patient, physician and care-home characteristics), also affect prescribing. However, these internal and external factors do not appear to affect prescribing uniformly, and poor prescribing practices in care homes continue to be observed. One intangible factor that has received little attention in this area of healthcare is that of organisational culture. This factor has been linked to quality and performance within other health organisations. Consideration of organisational culture within care-home settings may help to understand what drives prescribing decisions in this particularly vulnerable patient group and thus provide new directions for future strategies to promote quality care.