Objective: To assess the application of a structured process to consolidate the number of medication administration times for residents of aged care facilities. Design: A nonblinded, matched-pair, cluster randomized controlled trial. Setting and Participants: Permanent residents who were English-speaking and taking at least 1 regular medication, recruited from 8 South Australian residential aged care facilities (RACFs). Methods: The intervention involved a clinical pharmacist applying a validated 5-step tool to identify opportunities to reduce medication complexity (eg, by administering medications at the same time or through use of longer-acting or combination formulations). Residents in the comparison group received routine care. The primary outcome at 4-month follow-up was the number of administration times per day for medications charted regularly. Resident satisfaction and quality of life were secondary outcomes. Harms included falls, medication incidents, hospitalizations, and mortality. The association between the intervention and primary outcome was estimated using linear mixed models. Results: Overall, 99 residents participated in the intervention arm and 143 in the comparison arm. At baseline, the mean resident age was 86 years, 74% were female, and medications were taken an average of 4 times daily. Medication simplification was possible for 62 (65%) residents in the intervention arm, with 57 (62%) of 92 simplification recommendations implemented at follow-up. The mean number of administration times at follow-up was reduced in the intervention arm in comparison to usual care (−0.36, 95% confidence interval −0.63 to −0.09, P = .01). No significant changes in secondary outcomes or harms were observed. Conclusions and Implications: One-off application of a structured tool to reduce regimen complexity is a low-risk intervention to reduce the burden of medication administration in RACFs and may enable staff to shift time to other resident care activities.