In most countries, nurses are the largest group of health-care professionals that provide direct and indirect care to patients in a variety of health settings. The quality of care is strongly linked to their performance, and shortages of nursing staff cause suffering and diminished patient care. In 2008, it was estimated that there were 90 026 nurses in Iran, but health-care facilities need approximately 220 000 nurses in order to deliver optimal nursing care. This review article provides a detailed description of the nursing shortage and related factors in Iran. It is hoped that this will inform both Iranian and international policy-makers and administrators about the current situation in this country.