Background: Sleep has basic physiologic function and mental health stability that encouragernhealing process progressively from severely ill. We spend almost a third of our life sleeping.rnSleep disorder is a common complication of intensive care unit (ICU) stay. The etiology of sleeprnproblems in patients' intensive care units (ICUs) is ignorance by clinical staffs but it thought tornbe related to environmental factors and other none environmental factors. Sleep disruptionrnduring intensive care unit stay is frequent. Sleep disturbances can play greater role negatively inrnrecovery from critical illness. In critical ill patients, the happening of sleep deficit has shown tornbe more than 50 %rnObjective: To assess factors that disturb sleep quality of adult patients admitted to thernintensive care unit in the three selected Hospitals, Addis Ababa, Ethiopia 2020.rnMethodology: Prospective cross-sectional Design deployed in three-selected Hospitalsrnintensive care unit. A convenient sampling technique used to screen the participants. Modifiedrnfreedman self-reporting and personal characteristics questionnaire used to collect the data sleeprnaffecting environmental and none environmental factors from consented respondents who fulfillrnthe inclusion criteria at the time of ICU stay, at discharge or during the recovery phase who werernalert. Binary logistic and multivariable logistic regression used to obtain significant factors.rnResult: - The majority of study nearly two third of participants (63.7%) were suffered fromrnpoor sleep quality that were admitted in the ICU. The study demonstrated that sleep quality inrnthe ICU that mean score of sleep quality was 4.91+1.118 that significantly low compared withrnmean score of sleep quality was 6.33+1.245 at home (p=0.002). Length of stay, worrying,rnprevious admission history, mechanical ventilation, daytime sleepiness, and marital statusrnreported as stastically significant with poor sleep quality. The environmental factors were noise,rnpain, light and doctors/nurses activities that mean score of the factors were 6.6+1.270, 5.57+rn1.270, 5.10+1.570, and 5+1.61 respectively found sleep disrupting factors.rnConclusion and recommendation:-It is obvious that hospitalized patients are sufferedrnfrom poor sleep quality in the ICU. Therefore, there are many environmental and intrinsic factorsrncontributing for disturbing sleep quality in ICU that identified. I recommend daily sleep qualityrnassessment as vital sign and incorporate in the nursing care plan by providing adequate educationrnand training for ICU nursing staffs.