Chronic rhinosinusitis with nasal polyposis (CRSwNP) is associated with a high rate of disease recurrence following endoscopic sinus surgery (ESS). Type 2 disease is associated with a higher incidence of recurrence and is believed to impact disease resolution via interference with epithelial healing and pathogen immunity. We wished to verify if perioperative control of Type 2 inflammation with an anti-IL4/IL13 targeting monoclonal antibody and during the resolution period following surgery leads to better control of the disease long term. In this prospective, placebo-controlled, double-blinded trial. Thirty adult subjects with recurrent CRSwNP underwent ESS plus or minus 14 weeks of perioperative dupilumab, initiated 4 weeks (two injections) pre-ESS. Subjective and objective parameters of nasal patency, olfaction, quality of life (QoL), and adverse events were monitored up to 52 weeks post-ESS. Microbiological culture was performed to characterize pathogens colonization under both conditions. ESS safely improved subjective and objective measures of nasal patency, olfaction, and QoL in both groups. Olfaction was conserved longer in the dupilumab-treated group, with 33.3% of subjects presenting anosmia at 12 months after ESS in the dupilumab group compared to 50.0% with placebo. This was associated with persistent decreases in serum IgE, which were not seen with placebo treatment. No unusual safety signals were observed. Short-course adjuvant perioperative treatment with dupilumab is associated with improved long-term olfactory outcomes and persistent lowering of serum IgE.