The Drug Burden Index (DBI) is an evidence-based tool that associates medication exposure with functional outcomes in older people. Accredited clinical pharmacists performing medication reviews could consider including the DBI in their medication reviews to optimize prescribing in older people. To examine the impact of residential medication management reviews (RMMRs) performed by accredited clinical pharmacists on DBI in older people living in aged-care homes. A retrospective analysis was performed of a random sample of 500 de-identified RMMR reports from residents aged (mean +/- SD) 84 +/- 9.0 years who had medication reviews conducted by ten accredited clinical pharmacists from 1 January 2008 through 30 June 2008. The data on medication use were collected over 8 months across 62 aged-care homes. DBI scores were calculated at baseline, after the recommendations had been made by the pharmacist and after uptake of pharmacist recommendations by the general practitioner (GP). A statistically significant decrease (p < 0.001) in median DBI score was observed as a result of uptake of pharmacist recommendations by the GP. GPs were more likely to take up recommendations made by pharmacists that resulted in a decrease in DBI score than recommendations that resulted in an increase in DBI score (60.7% vs 34.6%, respectively). The mean decrease in DBI as a result of pharmacist recommendations was 0.12 (95% CI 0.09, 0.14) representing a 20% decrease in mean baseline DBI for residents. When GPs implemented pharmacists' recommendations, DBI decreased by a mean of 12% from baseline (mean decrease 0.07; 95% CI 0.05, 0.08). Most of the recommendations proposed by the pharmacists involved withdrawing benzodiazepines or reducing antipsychotic drug dosage. This is the first study in which DBI has been used as a tool to evaluate the impact of RMMRs conducted by accredited clinical pharmacists. The study demonstrates that pharmacist-conducted medication reviews can reduce prescribing of sedative and anticholinergic drugs in older people, resulting in a significant decrease in the DBI score.