Viral respiratory infection is thought to be the major contributing factor in the pathogenesis of bacterial sinusitis. It is still not clear why some patients suffer from recurrent sinusitis episodes, as information on the exact pathomechanism of how bacterial sinusitis develops as a complication of viral colds is still scarce. In this review, different mechanisms of how a viral infection may predispose some patients to recurrent bacterial sinusitis episodes are presented. Awareness of the fact that different mechanisms may exist behind this single diagnosis of recurrent sinusitis may be of help when diagnostic measures and treatments are planned for these patients.