Abstract: Objective To study sleep quality and cognitive status and their correlation in patients with persistent postural and perceptual dizziness (PPPD). Methods We assessed sleep quality and cognitive function among 70 patients with PPPD and 70 age-matched heathy volunteers using Mini-Mental State Examination (MMSE), Montreal Cognitive Assessment (MoCA), Pittsburgh Sleep Quality Index and polysomnography (PSG). Results The patients had a mean MMSE score of 25.10±3.87 and a mean MoCA score of 23.10 ± 6.11, both suggesting mild cognitive impairment of the patients. The mean PSQI score of the patients was 14.60 ± 2.06, suggesting moderate insomnia among the patients. The MMSE scores in 3 dimensions (attention, memory and recall ability) and the dimension scores of MoCA for visual space and executive ability, attention and delayed recall all showed significant positive correlations with PSQI scores for sleep quality, sleep latency, sleep duration, sleep efficiency, sleep disorders and daytime dysfunction. Conclusion Moderate sleep disorder and mild cognitive dysfunction are common in PPPD patients. Sleep quality is correlated with cognitive function among these patients, suggesting that improving sleep quality of the patients helps to improve their cognitive function.