Recently, eosinophilic chronic rhinosinusitis (ECRS) has become a very common disease in Japan. ECRS differs from other types of sinusitis in terms of clinical features, such as high rate of recurrence, olfactory disorders, ineffective macrolide therapy, and severe paranasal sinus shadow on CT imaging. The diagnosis of ECRS requires a biopsy of nasal polyps. Therefore, we tried to predict ECRS by evaluating CT images using the Lund-Mackay CT Scoring system (LMS). This retrospective study involved 105 patients who had undergone surgical treatment (ESS) between July 2011 and November 2012. These patients were divided into three groups based on patterns of pathogenesis: ECRS, fungal sinusitis (FS), and chronic sinus infection (CSI). The pathological classification of nasal polyp was graded on a 3-point scale according to the degree of eosinophilic infiltration. Total LMS score for the ECRS was 9.4±0.6 (mean±SE), which was significantly higher than for the other LMS scores (FS: 4.6±1.0, CSI: 5.8±0.2). LMS scores for the maxillary sinus were high for all three patterns of pathogenesis (ECRS: 1.4± 0.1, FS: 1.7±0.2, CSI: 1.3±0.1). The scores for the frontal and sphenoid sinus forECRS were significantly higher than the scores for the FS and CSI (maxillary sinus, ECRS: 1.5±0.1, FS: 0.4±0.2, CSI: 0.6±0.1; sphenoid sinus, ECRS: 1.4±0.2, FS: 0.2±0.1, CSI: 0.6±0.3). We assessed for and found a positive correlation between the bilateral LMS score and eosinophilic infiltration (rs＝0.665). Therefore, ECRS can be predicted by LMS without biopsy and LMS helps determine the management of chronic rhinosinusitis.