OBJECTIVE: Inflammation and platelet activation play a role in the pathogenesis of obstructive sleep apnea syndrome (OSAS). In this study, it was aimed to investigate the effectiveness of the systemic inflammation markers, the neutrophil-lymphocyte ratio (NLR), platelet-lymphocyte ratio (PLR) and WMR (white blood cell count (WBC) to mean platelet volume (MPV) ratio), in determining the severity of OSAS.