Background: Sleep pattern is a public health concern and is often considered a normal aging phenomenon. Aim of the study to assess the effect of sleep pattern on older adult's life. Research Design: A descriptive analytical design was used. Sample: Purposive sample of 350 older adult's. Setting: The study was conducted at outpatient clinic of Al Shaheed Ahmed Shawky hospital of older adults in El-Demerdash hospital affiliated to Ain shams university hospitals. Tools: Two tools were used for data collection. First tool: interviewing questionnaire was divided into four parts: Demographic data of older adult's, medical history of older adult's, knowledge of older adult's, reported practices of older adult's with sleep pattern. second tool: Observation checklist to assess health status of older adult's with sleep pattern. Results: 77.1% of older adult's had unsatisfactory level of total knowledge, 67.4% of older adult's had inadequate level of total reported practice, 90.9% of older adult's had a sleep pattern due to change in nature of sleep. Conclusion: There were a highly statistically significant relation between total older adult's knowledge and their educational level, (P.value <0.001), while with their age and monthly income at (p. value<.05). There was a highly statistical significant relation between older adult's total knowledge and their total reported practice (p. value <0.001). There was a statistical significant relation between older adult's total reported practice and their total older adult's health problems (p. value <0.05). Recommendations: Regular exercise, social activities, combined with sleep habits education are required to improve sleep and QoL in older adult's with sleep pattern disorders.