Prescription of medicines is a fundamental component of the care of older people, but evidence suggests that pharmacotherapy in this population is often inappropriate. Pharmacists have been involved in different approaches for the optimization of prescribing and rational medication use in older people. This article describes the different models of care in which pharmacists are involved in the optimization of pharmacotherapy in older people, and reviews the impact of these approaches on both process and outcome measures. The provision of pharmaceutical care, medication reviews and educational interventions by pharmacists in the nursing home, ambulatory and acute care settings are discussed. We selected systematic reviews, reviews and original studies, and for the latter, we focused more specifically on European publications published between 2001 and 2011. From the literature reviewed, it is clear that when pharmacists play a proactive role in performing medication reviews and in the active education of other healthcare professionals, pharmacotherapy for older patients is improved. However, the evidence of the impact of pharmacists' interventions on health outcomes, quality of life or cost effectiveness of care is mixed. Better results have been reported when pharmacists are skilled and work in the context of a multidisciplinary team. Opportunities remain for multicentre, European-based, pharmacist-intervention trials in all settings, to determine the effectiveness and economic benefit of pharmacist involvement in the optimization of pharmacotherapy in older people.