The role of osteitis of the middle turbinate and the condition of the paranasal sinus has evolved during the last few years. This prospective study was conducted to assess the effect of the middle turbinate especially the bony part on the inflammation of the paranasal sinus. Sixty-nine patients with the diagnosis of chronic or recurrent sinusitis, who failed to improve with medical treatment, underwent functional endoscopic sinus surgery (FESS). These patients were divided into 2 groups, group I the patients underwent FESS with partial middle turbinectomy (PMT). Group II the patients underwent FESS without (PMT) only biopsy was taken from the middle turbinate. Histopathological examination for the middle turbinate (mucosa and bone), also the mucosa and the bone of the sinus were studied in all patients. Ostietis and osteomylitis were found in (68%) of the middle turbinate bone and (53.6%) of the sinus bone .The turbinate bone might be responsible for chronic sinusitis. Follow up revealed that cure rate after FESS, there was not different in both groups. This indicates the partially resected middle turbinate does not improve the results.