Chronic rhinosinusitis (CRS) is a multifactorial disease. Predisposing factors can be divided into environmental and non-host factors, such as pollution, viral infections, smoking, fungus, and bacteria; general host factors, including genetic factors and immune deficiency; and local host factors, including persistent focal inflammation within the ostiomeatal complex. Evidence suggests that the underlying bone in the ostiomeatal complex is actively involved in the disease process of CRS. The evidence concerning a broad range of predisposing factors for CRS is reviewed.