Objective: To determine whether sleep duration is associated with self-rated health and quality of life in adults residing in New South Wales, Australia. Methods: Cross-sectional data from the 45 and Up Study were used. Sleep duration, self-rated health, quality of life and other health-related variables were assessed using a self-report questionnaire. Multi-nomial logistic regression models were used to examine whether sleep duration predicted self-rated health and quality of life. Results: The sample included 63,408 adults aged 45–95 years. After controlling for a range of covariates, (OR = 1.49, 95% CI 1.31–1.70), 6 h sleep (OR = 1.28, 95% CI 1.17–1.38) and P 9 h sleep (OR = 1.56, 95% CI 1.46–1.67) were associated with poorer self-rated health. Similarly, (OR = 1.80, 95% CI 1.57–2.07), 6 h sleep (OR = 1.36, 95% CI 1.24–1.49) and P 9 h sleep (OR = 1.41, 95% CI 1.30–1.53) were associated with poorer quality of life. Conclusion: Short and long sleep were significantly associated with poor self-rated health and lower quality of life in this large sample of middle aged and older Australian adults. While cross-sectional, these results add weight to recent data emphasising the importance of adequate sleep in physical and mental health.