Background Chronic frontal sinusitis is being treated with less invasive transnasal endoscopic treatments. Surgery relieves illness and prevents recurrence. Our study was conducted on 80 patients who suffer from frontal opacity with sinonasal polyposis and divided randomly into 2 groups: group A: 40 patients candidate for anterior ethmoidectomy without identification of frontal sinus ostium and group B: 40 patients candidate for anterior ethmoidectomy with identification of frontal sinus ostium. The study was conducted in the otolaryngology department  faculty of medicine Cairo university. Results CT score and sinonasal endoscopy score were statistically significantly improved postoperatively compared to preoperative scores in both groups. There are no significant differences between the 2 groups regarding recurrence rate and complications. Conclusion Ethmoidectomy without frontal sinusotomy is a potential substitute for frontal sinusotomy for the treatment of chronic frontal sinusitis with sinonasal polyposis, and it can achieve similar improvements in symptoms and radiological evidence of frontal sinusitis.