The aim of this study was to evaluate the efficacy of transnasal endoscopic marsupialization as a treatment modality in patients with postoperative maxillary mucoceles and to compare the efficacy of marsupialization via middle meatal antrostomy with that of marsupialization via inferior meatal antrostomy. The study design was a retrospective clinical series and the setting was a tertiary referral center. After obtaining approval from the local ethics committee, we reviewed the medical records of 39 consecutive patients with postoperative maxillary mucoceles who were diagnosed and treated at the Department of Otolaryngology, Chang Gung Memorial Hospital, Taiwan, from 2004 to 2009. Transnasal endoscopic marsupialization was performed on 32 patients (34 sides) with postoperative maxillary mucoceles. All patients were followed for more than 12 months after surgery, and recurrence was noted in five patients (14.9%). Recurrence was experienced by five patients who underwent inferior meatal antrostomy and zero patients who underwent middle meatal antrostomy; thus, a statistically significant difference (p = 0.04) was observed. Transnasal endoscopic marsupialization is an effective modality for postoperative maxillary mucoceles and results in reduced morbidity. The use of middle meatal antrostomy in particular is preferred.