Objective Assessment the effect of topical application of mitomycin‐C (MMC) after endoscopic removal of antrochoanal polyp (ACP) on its recurrence rate. Methods This prospective study was done on patients with ACP. Endoscopic nasal surgery has been done to remove the polyp after wide middle meatal antrostomy. The patients were categorized into two groups. In MMC group, after endoscopic ACP removal, MMC on a piece of cotton was topically applied inside the maxillary antrum in the suspected site of ACP origin. A second group was used as a control group without MMC application. Results The study included on 40 patients; 20 patients in each group. Topical MMA application was easily performed. No granulation, crust, infection, or bleeding was reported in all cases of both groups. Recurrent polyp was not reported in MMC group, while recurrent polyp was detected in four cases (20%) in control group without MMA application with statistically significant difference (P = .035). Conclusion Topical MMC application inside the maxillary sinus after endoscopic removal of the ACP is safe, easy, and effective. Level of evidence 2c.