Sleep is a physiological process essential to humans and their normal functioning and the need for rest and comfort is an important need for maintaining a good quality of life. Adequate rest and sleep is essential for physical and psychosocial functioning of the individual. The main aim of the study was to assess the level of stress and sleep among critically ill patients admitted in the critical care unit of Sree Mookambika Medical College Hospital, and to find out the association between the level of stress and sleep with selected demographic variable and clinical variable among critically ill patients. The study was non-experimental descriptive research with quantitative research approach. The study was conducted in Sree Mookambika Medical College Hospital, Kulasekharam.

30 samples were selected by using convenience sampling technique. The tools used for the data collection were demographic variables, clinical variables, Richards - Campbell Sleep Questionnaire and Environmental Stressor Questionnaire. The data was analysed and interpreted in terms of objective, descriptive and inferential statistics. The study findings are 10% sample had mild stress, 33.33% sample were very stressful, 56.66% sample were extremely stressful. 13.33% patients had normal range of sleeplessness, 20% had mild range of sleeplessness, 30% had moderate range of sleeplessness and 36.66% had severe range of sleeplessness. There is a significant association between level of sleep and clinical variable such as days in ICU.