Objectives: The aim of this study was to compare the efficacy of bioabsorbable steroid-eluting sinus stents versus absorbable Nasopore packs after endoscopic sinus surgery (ESS) for the treatment of chronic rhinosinusitis (CRS). Methods: One hundred eighty-one patients with CRS who underwent ESS were randomly assigned to receive a steroid-eluting sinus stent in one ethmoid sinus cavity, whereas the contralateral control side received a Nasopore pack. Endoscopic evaluations were performed 14, 30, and 90 days after the ESS. Postoperative intervention, polyp formation, adhesions, and middle turbinate (MT) position were assessed as efficacy outcomes. Results: The stents were successfully deployed in all 181 sinuses. Thirty days after the ESS, the stents significantly reduced the need for surgical intervention compared to the Nasopore (P < .0001). The percentage of cases with polyp formation was significantly lower on the stent sides compared with the Nasopore sides (P < .0001) at 14, 30, and 90 days after ESS. The percentage of severe adhesion was significantly lower on the stents sides than on the Nasopore sides at postoperative day 90 (P = .0003), whereas they were not significantly lower at postoperative days 14 and 30. There were no significant differences between the stent sides and the Nasopore sides regarding the frequency of MT lateralization at all end points. No device-related adverse events occurred. Conclusions: Our study demonstrated significant improvement in the early postoperative outcomes by reducing the need for postoperative surgical intervention and polyp formation using steroid-eluting stents when compared with absorbable Nasopore packs. The steroid-eluting sinus stents and the Nasopore packs were each effective in preserving the ethmoid sinus patency and in preventing MT lateralization. A further prospective cohort study with long-term postoperative outcomes is warranted.