Promoting a peaceful environmental place to sleep in the hospital is very complicated and challenging. Even though a patient may try to sleep in the hospital, it may not be refreshing or restorative because of the following factors like environmental, physiological and psychological. These factors can work concomitantly, making sleep virtually impossible for some patients. Nurses can help their patients by understanding what influences their disturbing sleep patterns. The aim of the study is to know the factors that affect the quality of sleep in hospitalised patients. A cross-sectional questionnaire study was conducted among 100 hospitalised patients of Saveetha Dental College. Their answers were compared with the Farsi Pittsburgh sleep index and graphs have been plotted. Inclusion criteria: Selection criteria includes age greater than or equal to 18 years and completely conscious patients, patients hospitalized for more than two weeks. Exclusion criteria: Recently hospitalized patients , patients who received hypnotics or sedative drug over the last 24 h, history of any major organ failure that may be associated with impaired conscious level and patients with sleep apnea were excluded.Statistical analysis was done using the SPSS software version 22. Descriptive statistics were expressed by means of frequency and percentage. Chisquare tests were used to find the association between the variables.We found that environmental factors affect the quality of sleep by 40% of the study population , Physiological factors affect 30% of the study population and Psychological factors affect the remaining 30% of the study group.The environmental and physiological factors have more influence on the disturbed sleep pattern on hospitalized patients. The proper preventive measures must be taken to improve the sleep quality.