The survey was conducted in Senegal in April 2001 on a representative sample of providers and clients. Results show that access to medicines in Senegal was limited for three main reasons: (1) the supply of drugs was inadequate, and even critical drugs were often missing in health centres, and were somewhat less in pharmacies; (2) the health infrastructures appeared insufficient to cover the needs of the whole population, creating high opportunity costs; (3) the cost of the drugs prescribed was higher than the minimum price, sometimes exceeding the capacity of poorer people, although high cost was seldom reported as the main reason for not acquiring prescribed drugs. Improving access to medicine is a priority to help reduce health inequalities in developing countries.