To determine the extent to which evidence-based medication safety practices have been implemented in public and private mental health inpatient units across Australia. The Reducing Adverse Medication Events in Mental Health survey was piloted in Victoria, Australia, in 2015, and rolled out nationally in 2016. In total, 235 mental health inpatient units from all States and Territories in Australia were invited to participate. The survey included questions about the demographics of the mental health unit, evidence-based strategies to improve prescription writing, the administration and dispensing of medicines and pharmacy-led interventions, and also questions relating to consumer engagement in medication management and shared decision-making. The response rate was 45% (N = 106 units). Overall, the survey found that 57% of the mental health units had fully or partially implemented evidence-based medication safety practices. High levels of implementation (80%) were reported for the use of standardized medication charts such as the National Inpatient Medication Chart as a way to improve medication prescription writing. Most (71%) of the units were using standardized forms for recording medication histories, and 56% were using designated forms for Medication Management Plans. However, less than one-fifth of the units had implemented electronic medication management systems, and the majority of units still relied on paper-based documentation systems.Interventions to improve medicine administration and dispensing were not highly utilized. Individual patient-based medication distribution systems were fully implemented in only 9% of the units, with a high reliance (81%) on ward stock or imprest systems. Tall Man lettering for labelling was implemented in only one-third of the units.Pharmacy services were well represented in mental health units, with 80% having access to onsite pharmacist services providing assessments of current medications and clinical review services, adverse drug reaction reporting and management services, patient and carer education and counselling, and medicines information services. However, pharmacists were involved in only half of medical reconciliations. Their involvement in post-discharge follow-up was limited to 4% of units. Gaps in medication safety practices included limited use of individual patient supply systems for medication distribution, a high reliance on ward stock systems and high reliance on paper-based systems for medication prescribing and administration. With regards to service provision, clinical pharmacist involvement in medical reconciliation services, therapeutic drug monitoring and interdisciplinary ward rounds should be increased. Discharge and post-discharge services were major gaps in service provision.