Stress is everyday life’s reality. Everyone is struck by it in one way or the other. No one is safe from it. This study aimed to assess factors that can cause stress among nurses working in critical care unit and to find the relation between these factors and demographic data, it is a descriptive study done in Khartoum, hospital and Omdurman hospital June -July 2015. 56 nurses enrolled in the study, selected randomly. data were collected after applied self-administer questionnaire .in the results most of the respondents strongly agreed that lack of practice and a shortage of staff and prolonged period of working without break, and lack of support and improper communications between their college and improper environments all these factors cause stress for nurses in the critical care unit. Conclude: majority of the nurses had severe stress with different stress factors and highly significant association between these factors and the demographic variable which support our hypothesis