Aim The study aims to determine the impact of a quality improvement intervention on how accurately and suitably medicines are supplied to residents of residential aged‐care facilities (RACFs). Methods Between September 2012 and January 2013, pharmacy‐supplied dose administration aids (DAAs) were audited at 45 Victorian RACFs (Australia). RACFs had previously received an intervention (education session/toolkit) and were involved in an earlier DAA audit. Recently supplied DAAs containing regular medicines were compared to prescriber‐prepared medicine charts to identify, and classify risks of, inaccurate or unsuitable packing incidents. Results Of 2389 DAAs audited for 983 residents, 770 incidents in 502 DAAs were identified. The overall DAA incident rate increased significantly from 11.5% pre‐intervention to 21.0% post‐intervention (P < 0.001). The proportion of DAAs affected by incidents classified as ‘insignificant’ or ‘minor’ risk increased post‐intervention (P < 0.001). Conclusions Further wide‐scale evaluation of RACF medicine supply services is needed. Interventions that are effective in reducing DAA incidents should be explored.