Purpose: To assess associations of shift work with sleep quality in police. Methods: Participants were officers enrolled in the Buffalo Cardio-Metabolic Occupational Police Stress (BCOPS) study (2004-2009). A work history database, containing day-by-day account of start time and work hours, was used to define shifts as day (start time = 7 or 8 am), afternoon (4 pm) or night (8 or 9 pm). Sleep quality (good/poor) was determined using the Pittsburgh Sleep Quality Index (PSQI) questionnaire. Poisson regression was used to estimate prevalence and prevalence ratios (PR) of poor sleep quality associated with shift work. Results: The prevalence of poor sleep quality was 54% (95% confidence interval (CI): 49.1, 59.4) among the 363 officers with complete data. Half of the study participants worked on day shift. Prevalence of poor sleep quality was 70% (PR=1.70, 95% CI: 1.34, 2.14) higher among night shift officers and 49% (PR=1.49, 1.17, 1.91) higher among those on afternoon shift relative to officers working on day shift. The association also depended somewhat on smoking status, body mass index, and physical activity. Differences in prevalence of poor sleep quality between night and day shift officers were larger among smokers, overweight/obese participants, and those with low physical activity levels. Conclusion: Results indicate that night shift work is associated with poorer sleep quality among police officers. Future longitudinal studies could assess whether shift work predicts poor sleep quality and elucidate mechanisms by which lifestyle factors moderate this association.