To evaluate the correlation between radiological and endoscopic findings in cases of chronic headache. METHODOLOGY: The study includes 300 patients who presented to the OPD of a tertiary level centre with headache. RESULTS: Endoscopic and CT abnormalities were detected in 265/300 (88.3%) patients. Most common abnormality was a septal spur impinging on lateral nasal wall seen in 94 cases (35.4%), followed by inferior turbinate hypertrophy, concha bullosa, accessory maxillary sinus ostium, paradoxical curved middle turbinate, polyposis and frontal osteoma. A majority of patients had associated changes in the sinuses as well. CONCLUSION: The study highlights the correlation between radiological and endoscopic findings of sinonasal disease as a cause of headache. Abnormalities and variations in endonasal anatomy, functional or anatomical or a combination of these variations caused narrowing of OMU, which predisposed patients to sinonasal disease and headache.