<i>Background:</i> Stress is frequently associated with critical care nursing. Nurses experience stressful situations in their daily working environments. <i>Objective:</i> To study occupational stress and stressors experienced by nurses working in intensive care units at public hospitals of Khartoum state. <i>Methods:</i> A cross-section study was carried at 14 public hospitals. A sample of 139 nurses was chosen by a simple random sampling technique. The nurses were interviewed by a questionnaire including Expanded Nursing Stress Likert Scale and the main factors that contribute to work-related stress. Data was managed by statistical package for social science version 20. <i>Results:</i> The mean score of overall occupational stress experienced by nurses was 1.88 with standard deviation of 0.50. The analysis of stress domains revealed that nurses rated the death and dying situations as the most stressful (M=2.23; SD=0.56), followed by workload (M=2.16; SD=0.61) and problems with supervisors (M=2.07; SD=0.82). The mean of occupational stress perceived when dealing with patients and their families was 1.92 ± 0.62 and stress due to uncertainty concerning treatments was 1.92 ± 0.68. While less occupational stress encountered in situations of problems with peers (M=1.89; SD=0.72), inadequate preparations (M=1.87; SD=0.74) and conflicts with physicians (M=1.73; SD=0.68). The least stressful domain was discrimination (M=1.10; SD= 0.82). Perceived occupational stress is significantly affected by socio-demographic determinants of participants such as marital status, working experiences and the type of ICU. <i>Conclusions:</i> The main sources of stress experienced by critical care nurses in Khartoum state hospitals were death and dying situations and workload. Work experiences were found to be significantly associated with stress perception in critical care nurses. The findings suggest that perceived stress does vary within different types of intensive care units.