The goal of this study was to assess the relationship between the severity of obstructive sleep apnoea (OSA) and liver stiffness measurement (LSM), one of the most accurate noninvasive screening tools for liver fibrosis in nonalcoholic fatty liver disease.The study included 147 patients with at least one criterion for the metabolic syndrome, assessed by polysomnography for suspected OSA. LSM was performed using transient elastography (FibroScan). Significant liver disease and advanced liver fibrosis were defined as LSM ≥7.3 and ≥9.6 kPa, respectively.23 patients were excluded because of unreliable LSM. Among 124 patients, 34 (27.4%) had mild OSA, 38 (30.6%) had moderate OSA and 52 (42.0%) had severe OSA. LSM values were 7.3- <9.6 kPa in 18 (14.5%) patients and ≥9.6 kPa in 15 (12.1%) patients. A dose-response relationship was observed between OSA severity and LSM values (p=0.004). After adjustment for age, sex, metabolic syndrome and insulin resistance, severe OSA was associated with an increased risk of LSM ≥7.3 kPa (OR 7.17, 95% CI 2.51-20.50) and LSM ≥9.6 kPa (OR 4.73, 95% CI 1.25-17.88).In patients with metabolic comorbidities, severe OSA is independently associated with increased liver stiffness, which may predispose to a higher risk of significant liver disease and poorer prognosis.