The aim of this study was to investigate the effects of total nocturnal sleep time and siesta on hepatocellular carcinoma (HCC) risks in chronic HBV infected individuals. This research was retrospective. A case–control study with 226 HCC patients and 375 controls enrolled was conducted. All subjects were chronic HBV infected. The total nocturnal sleep time and siesta or not were recorded by interview. We found that the total nocturnal sleep time and siesta were associated with the incidence of HCC (p < 0.001). The adjusted OR of HCC for the subjects with the shortest total nocturnal sleep time (≤ 6 hs) was 2.557 (p = 0.032), relative to those who slept between 6 and 8 h. The patients who slept ≥ 8 h experienced much lower risk. The adjusted OR of HCC for subjects with total nocturnal sleep time ≥ 8 h were 0.507 (p = 0.005) relative to those who slept 6–8 h. The subjects without siesta habit experienced a higher risk of HCC compared to those who with the siesta habit (adjusted OR 2.157, p = 0.001). These findings indicate that lack of nocturnal sleep is a potential risk factor for HCC in chronic HBV infected individuals whereas the siesta is a protective factor.