BACKGROUND: Obstructive sleep apnoea (OSA) is considered an important risk factor of cardiovascular diseases (CVDs). Epicardial fat (EF) thickness and adipocyte fatty acid-binding protein (A-FABP) may be important links to accelerated atherosclerosis observed in patients with OSA. The aim was to evaluate the relationship between EF thickness and A-FABP levels in patients with OSA. METHODS: 66 patients (of which, 60 were males) of average age 55.6 ± 8.8 years, with newly diagnosed OSA were enrolled in this study. All patients underwent a sleep study, anthropometric parameters were measured, laboratory analysis and echocardiography with EF thickness measurements were collected. Patients were divided into two groups: Group 1: EF < 1mm; Group 2: EF > 1mm. RESULTS: Epicardial fat was present in 51 patients (77.3%). A positive correlation was found between A-FABP levels and % of body fat (r=0.452, p=0.0002). After adjusting to % of body fat, there was no significant difference found in A-FABP levels in the two groups divided. CONCLUSIONS: This study found a positive correlation between serum A-FABP level and % of body fat in patients with moderate to severe obstructive sleep apnoea. No significant difference was found between both groups.