Background: Severe traumatic brain injury is a global problem that leads to morbidity and mortality particularly among young people. So this study aimed to determine the effect of implementing standardized designed nursing guidelines on outcomes of severe traumatic brain injury patients. Quasi-experimental research design was utilized. Setting: this study was carried at Trauma intensive care unit at Sohag University Hospital. A purposive sample of 70 adult severe traumatic brain injury patients were matched & randomly assigned into 2 equal groups. Three tools were used; Tool I: Traumatic brain injury assessment sheet, Tool II: Neurological assessment sheet, Tool III: Clinical outcome evaluation sheet. Results of current study revealed a statistically significant difference between study and control group regarding clinical outcomes includes prolonged Mechanical Ventilation, Re-intubation and number of death in addition to occurrence of complications as fever, bed sores and infection. Conclusions: application of standardized designed nursing guidelines improves outcomes and help to reduce occurrence of complications for patients with Severe Traumatic Brain Injury. Recommendation: Future researches are needed to examine the effect of the standardized designed nursing guidelines in the different age groups such as older adults and child to improve the outcomes.