Abstract: Objective To investigate the expressive levels of ODC and GAD65, and detect their clincopathological significances in the benign and malignant lesions of rhinosinus. Methods EnVision immunohistochemical method was used for determining expression levels of ODC and GAD65 in the routinely paraffin-embedded sections from specimens of adenocarcinoma of rhinosinus and peritumoral tissues (n=67), sinonasal inverted papillomas (n=48), and chronic sinusitis and nasal polyps (n=35). Results The positive expression rates of ODC and GAD65 in adenocarcinoma of rhinosinus (73.1%，61.2%) were significantly higher than those in peritumoral tissues (28.4%，χ²=17.26，P<0.01；20.9%，χ²=13.28，P<0.01), sinonasal inverted papillomas (20.8%，χ²=8.66，P<0.01；27.1%，χ²=5.10，P<0.05), and chronic sinusitis and nasal polyps (11.4%，χ²=28.28，P<0.01；17.1%，χ²=14.98，P<0.01). The postive rates of ODC and GAD65 in highly-differentiated adenocarcinoma, no-metastasis of lymphnode, no-infiltration of regional tissues or organs (T2N0M0) were significantly lower than those in low-differentiated adenocarcinoma, metastasis of lymphnode, infiltration of regional tissues or organs (T3N0M0，T4N1M0) (P<0.01). Conclusion Changes of enzymatic activity of ODC and GAD65 might be important biological markers for reflecting the carcinogenesis, progression, bological behaviors and prognosis of adenocarcinoma of rhinosinus.