Increasing efforts are being made to improve drug-use practices and prescribing behaviour in developing countries. An essential tool for such work is an objective and standard method of assessment. We present here a set of drug-use indicators produced and tested in twelve developing countries. We describe practical applications, which include the use of indicators to increase awareness among prescribers in Malawi and Bangladesh, to identify priorities for action (eg, polypharmacy in Indonesia and Nigeria, overuse of injections in Uganda, Sudan, and Nigeria, and low percentage of patients who understood the dosage schedule in Malawi), and to quantify the impact of interventions in Yemen, Uganda, Sudan, and Zimbabwe.