A number of different systems exist for staging computerized tomography (CT) scans in rhinosinusitis. The aim of this study was to determine which of four selected staging systems, currently in common use facilitated the highest level of agreement. The systems studied were those by Jorgensen (1991), May and Levine (1991), Lund and Mackay (1993) and Newman (1994). Ten observers independently assessed 10 representative films. In our assessment, the Lund and Mackay system facilitated the highest level of both inter-observer and intra-observer agreement of the four systems tested. We recommend it be adopted as the standard method of measuring the extent of disease, as depicted by CT scanning for chronic. rhinosinusitis.