OBJECTIVES: Medicines included in a benefit package scheme may be subject to co-payments by patients. This study aims to survey co-payment regulation for medicines, including mechanisms for reduction and exemption. *** METHODS: A survey was conducted with competent authorities for pharmaceutical pricing and reimbursement policies and public payers in 46 countries, including all 28 European Union Member States, further countries in the WHO European region (which includes some countries in Central Asia), Canada and South Korea. Data pertain to the year 2018. *** RESULTS: Apart from Armenia, Belgium, North Macedonia and South Korea, no co-payments are charged for medicines provided to inpatients. For outpatient medicines, however, patients are asked to co-pay in defined cases in all countries except for Malta, Kazakhstan and Kosovo which offer a limited number of medicines in the public sector for free. The most frequently applied type is percentage co-payment which is in place in 30 countries, thereof the sole co-payment in 18 countries. This co-payment type requires patients to pay a certain percentage of the pharmacy retail price. The extent of percentage co-payments usually depends on the assessed therapeutic value of the medicine. 20 countries charge a prescription fee on reimbursable medicines (6 of these countries apply solely this type of co-payment), which is usually a defined fixed amount for the whole country (Canada, Italy and the UK apply regional prescription fees). A deductible requiring patients to pay upfront up to a certain threshold is applied in 9 countries (sole co-payment policy in 5 countries). All surveyed countries that charge co-payments on medicines have mechanisms in place to exempt certain medicines or population groups, or to charge lower co-payments. Specific diseases are the most common reasons for an exemption (31 countries) or a reduction (18 countries). Further common causes include age, usually children and youth (exemption in 18 countries, reduction in 13 countries), income (exemption in 16 countries, reduction in 15 countries), retirement status (exemption in 9 countries, reduction in 16 countries) and disability (exemption in 10 countries, reduction in 11 countries. *** DISCUSSION: Co-payments for outpatient medicines are frequently applied but their design varies between countries. A mix of different co-payment types is common. In order to not impede access to medicines, co-payment regulation must be cautiously implemented. In addition, further components need to be considered, such as the price of a medicine (which directly impacts the payment in case of percentage co-payments) and the number of reimbursable medicines as a small list of reimbursed medicines may constitute a barrier of accessibility.