Very little is known about the actual harm that occurs to patients in developing or transitional countries, although the available evidence suggests that they may have an even higher risk of suffering patient harm. Understanding the magnitude of the problem and the underlying factors represents the first step towards improvement. The World Health Organization (WHO) is making a concerted effort, in different parts of the world, to identify the main issues affecting safe care in developing and transitional countries and to use these data to begin to developing and implementing effective solutions.