Developed countries have largely achieved universal health care coverage, while many developing countries are implementing steps to increase healthcare coverage. While the objective is the same, the healthcare systems and policies across countries differ across countries leading to different levels of access to medicines. To understand which systems and policies can lead to better access, we need a measure to evaluate how well countries do in terms of providing access to medicine for their populations. In this paper, we develop a Country Access to Medicines Index that compares and ranks countries on access to medicine outcomes. This index is based on five pillars – ease of accessibility to healthcare workers and facilities, awareness of disease diagnosis and treatment, availability of medicines, affordability of medicines and adherence to right treatment. We identify key variables in each of these pillars and compare and rank 30 countries with more than 60% of the world’s population on each of these variables,  at an aggregate level on each pillar, and overall. We draw upon IMS data as well as international and country level sources to obtain the data needed for the measures. We then look at the health systems and policies in these countries to identify features that lead to better performance on the index. We find that five broad factors can help explain access to medicines performance. First is the level of financing of healthcare, especially reimbursement coverage. Second is a structured and transparent pricing and patient access system that prioritises resource allocation to high need diseases and patients and sets economically justifiable prices. Third is the level of development of healthcare infrastructure. Fourth, is the provider and pharmacy incentives that promote appropriate use of medicine. And finally, a system that ensures the proper implementation of health policy initiatives.