Several clinical studies show a gender dimorphism of immune and organ responsiveness in the susceptibility to and morbidity from shock, trauma, and sepsis. However, there are conflicting reports on the role of gender in outcomes. Animal studies of shock, trauma, and sepsis have confirmed that alterations in immune and organ functions are more markedly depressed in adult males and in ovariectomized and aged females. In this review, we discuss the effect of estrogen on liver, intestinal, splenic, and renal functions in an experimental model of sepsis, trauma, and reperfusion injury. To establish the role of gender in the outcome of these patients, more studies in clinical and experimental settings are required to determine whether gender-specific responses are global across the injuries or are observed in specific injury situations. Studies are also needed to delineate underlying mechanisms responsible for differences between males and females. The findings gained from the experimental studies will help in designing innovative therapeutic approaches for the treatment of sepsis, trauma, and reperfusion injury patients. © 2012 Japanese Society of Anesthesiologists.