Objective Practices vary regarding the timing of discharge after sinonasal surgery. This study aimed to examine the cost-effectiveness of same-day discharge compared to next-day discharge after sinonasal surgery. Methods A retrospective single-surgeon audit of sinonasal surgery over a 12-month period was performed. Demographic and clinical details, including distance travelled home, timing of discharge, hospital re-presentation, and complications, were collected and compared between the same-day discharge and next-day discharge groups. A cost-effectiveness analysis was performed. Results A total of 181 patients were identified; 117 underwent day-case surgery, of which 6 re-presented to the emergency department. Sixty-four patients stayed overnight after surgery, and six of those patients re-presented to the emergency department. The per patient cost was $3262 for day-case sinonasal surgery and $5050 for those admitted overnight after surgery (p < 0.001). Conclusion Routine same-day discharge after sinonasal surgery is achievable, safe and cost-effective.