OBJECTIVESIn developing countries, medicines are the largest proportion of out-of-pocket health expenses as medicines are rarely subsidized. Medicine prices are variable and often high and as a result medicines are frequently unaffordable for a large proportion of the global population. In 2003, the World Health Organisation and Health Action International (HAI) published a manual entitled “Medicine Prices – a new approach to measurement”. This innovative manual describes a method to collect price information reliably, facilitating national and international comparisons. METHODS: The process involves the collection of retail price and availability data from a sample of registered pharmacies in the public, private or “other” sector, in each of four randomly selected regions of a country or state. A core list of medicines is surveyed, plus a supplementary list of locally important medicines. For each medicine, prices are sought for the innovator brand, and the lowest priced generic equivalent at the facility surveyed. Government procurement prices are also collected. Prices are compared to an international reference price. RESULTS: The affordability of a selection of standard treatment regimens is assessed based on the number of days the lowest paid unskilled government worker needs to work to purchase the treatment. Guidance is also given as to how to analyze price components (taxes, mark-ups etc.) applied in the distribution chain from the manufacturer to the patient. CONCLUSIONS An Excel workbook, which accompanies the manual, is used to double enter, error check and analyze the data. The manual also includes a chapter which outlines a range of policy option to lower medicine prices based on the evidence gathered. Currently over 40 national or state surveys are underway or completed (in addition to 9 pilot surveys). To aid price transparency, survey data, reports and other information is freely available on HAI's website (www.haiweb.org/medicineprices).