Nurses' lack of knowledge is considered to be one of the most significant factors contributing to medication administration errors. Although any medication can cause harm when used improperly, high alert medications are more likely to cause harm, and the harm they produce is likely to be more serious.As well, nurses working in intensive care units are always overloaded; they are dealing with more than one critically ill patient at a time, managing emergent situations and administering a lot of medications to those patients. Most of those medications are categorized as" high alert medications" .Moreover, there are scanty researches done into this area. Therefore, there are intense need to assess nurses' knowledge and practice regarding those types of medications.