Objective To investigate the incidence and severity of discomforts experience,such as pain,anxiety and sleep deprivation in patients in the intensive care unit(ICU),in order to explore the relationship between the discomfort experience and therapeutic measures,nursing procedure and the environment of ICU.Methods A total of 142 critically ill patients,who stayed in ICU for>24 h between Jun 2006 and Dec 2007 were included in the analysis.All patients were interviewed 3 to 7 days after discharging from ICU.The incidence of discomfort experience such as pain,anxiety,thirst,sleep deprivation and subjective feeling of noise were recorded.The factors that influenced the discomfort experience were analysed.Results The incidences of pain,anxiety,thirst,sleep deprivation and subjective feeling of noise were 35.2%,51.9%,88.9%,55.8% and 47.2%,respectively in all these patients.The painful experience of using mechanical ventilation was recalled by 78.0% of the patients.Airway suctioning was experienced as discomfort by 52.5% of the patients.Pain was closely related to airway suctioning,intravenous injection and indwelling gastric tube.The anxiety was intimately related to the environmental noise,intravenous injection and mechanical ventilation.Sleep deprivation was caused by noise,mechanical ventilation,airway suctioning,indwelling gastric tube and intravenous injection,etc.Conclusion The incidence of discomfort experience in critically ill patients is high.Therapeutic intervention,nursing procedure and the environmental noise are the main causes of patients’ experience of discomforts.