Objective : Describe what hospitalization in an intensive care unit (ICU) means to critically ill patients. Method : This is a research project with a phenomenological approach. It includes nine adults between the ages of 24 and 80 who were critically ill and hospitalized in an intensive care unit. Information was collected through in-depth interviews and analyzed pursuant to the scheme proposed by Cohen, Kahan and Steeves. The study was conducted in Medellin, Colombia, between April and October 2006. Results : The study made it possible to describe the “ harshness ” of the experience and the difficulties that emerged during the illness, as well as the physical and psychological suffering and some of the conditions that contributed to suffering. Discussion : The experience of having a critical illness and being hospitalized in an ICU is harsh, given the suffering occasioned by the effects of the illness, the elements used in treatment, and the procedures conducted to resolve the illness. Conclusion: The manifestations of an illness in the organism and in the person, medical and surgical interventions, and nursing pro­cedures can cause suffering that contributes to the harshness of the experience of being critically ill.