Background There is a paucity of high-quality evidence based on clinical endpoints for routine cleaning of shared medical equipment. We assessed the effect of enhanced cleaning and disinfection of shared medical equipment on health-care-associated infections (HAIs) in hospitalised patients. Methods We conducted a stepped-wedge, cluster randomised, controlled trial in ten wards of a single hospital located on the central coast of New South Wales, Australia. Hospitals were eligible for inclusion if they were classified as public acute group A according to the Australian Institute of Health and Welfare, were located in New South Wales, had an intensive care unit, had a minimum often wards, and provided care for patients aged 18 years or older. Each cluster consisted of two randomly allocated wards (by use of simple randomisation), with a new cluster beginning the intervention every 6 weeks. Wards were informed of their allocation 2 weeks before commencement of intervention exposure, and the researcher collecting primary outcome data and audit data was masked to treatment sequence allocation. In the control phase, there was no change to environmental cleaning practices. In the intervention phase, a multimodal cleaning bundle included an additional 3 h per weekday for the dedicated cleaning and disinfection of shared medical equipment by 21 dedicated cleaning staff, with ongoing education, audit, and feedback. The primary outcome was the number of confirmed cases of HAI, as assessed by a fortnightly point prevalence survey and measured in all patients admitted to the wards during the study period. The completed trial is registered with Australia New Zealand Clinical Trials Registry (ACTRN12622001143718). Findings The hospital was recruited on July 31, 2022, and the study was conducted between March 20 and Nov 24, 2023. We assessed 220 hospitals for eligibility, of which five were invited to participate, and the first hospital to formally respond was enrolled. 5002 patients were included in the study (2524 [50