Background: Endoscopic sinus surgery (ESS) represents the overall accepted type of surgical treatment for chronic rhinosinusitis with nasal polyposis (CRSwNP) refractory to medical treatment. Presence of postoperative Middle meatal adhesions are a potential cause of surgical failure. Triamcinolone is recently proposed as a solution for these adhesions. Objective: This study was designed to evaluate the effect of steroid loaded middle meatal gelfoam sheet on endoscopic sinus surgery outcome regarding middle meatal adhesions and synechiae formation in patients with CRSwNP refractory to medical treatment. Patients and Methods: This prospective, randomized, single-blinded, placebo-controlled study was conducted on 62 nasal cavities of 31 patients with bilateral CRSwNP. At the end of ESS, randomly gelfoam sheet loaded with triamcinolone was placed in one middle meatus and another gelfoam sheet loaded with saline in the contralateral middle meatus for 1 week. Results: Our results as regards topical application of steroids to the middle meatus showed a statistically significant difference between the steroid side and the saline (control) side in reduction of synechia formation after ESS. Therefore, topical application of steroids is effective in minimizing synechiae formation after ESS. It is also safe and no local or systemic complications were noted during the study. Conclusion: Results of our study demonstrated that the steroid loaded middle meatal gelfoam sheet has a role in minimizing middle meatal adhesions and synechiae formation after endoscopic sinus surgery for patients with CRSwNP