Impaired sleep quality is frequently associated with hypertension.The present study aims to examine self-reported sleep quality of patients with white coat hypertension. A total of 74 subjects who were evaluated in a cardiology outpatient clinic, including 39 normotensive subjects and 35 patients with white coat hypertension between the ages of 20 and 65 were included in this study. Patients with elevated office blood pressure (≥140/90mm Hg) and normal 24-h and daytime ambulatory blood pressure (<125/80mm Hg and <130/85mm Hg, respectively) were defined as white coat hypertension. Patient's sleep quality was evaluated using the Pittsburgh sleep quality index. Global Pittsburgh sleep quality index score was significantly higher in patients with white coat hypertension than normotensive subjects (7.2 ± 3.7 vs. 5.1 ± 3.8, P = 0.01). Poor sleep quality was present in 65% of patients with white coat hypertension, and in 30% of the normotensive group (P = 0.003). A multiple logistic regression analysis showed that white coat hypertension (odds: 6.7 (95% confidence interval [CI] 1.22-36.64), P = 0.03) and female gender (odds: 10.1(95% CI 1.35-76.32), P = 0.02) were independent predictors of poor sleep quality. In conclusion, white coat hypertension seems to be associated with impaired sleep quality. © 2014 Japanese Society of Sleep Research.