OBJECTIVE: Response to dupilumab for chronic rhinosinusitis with nasal polyps, albeit almost always excellent, is still not predictable. Our study focuses on the role of body mass index (BMI) on the efficacy of dupilumab. METHODS: We present a retrospective multicentre study of 106 patients on dupilumab, stratified in 3 subgroups of BMI. The main therapeutic outcomes investigated were Nasal Polyp Score (NPS), Sino-Nasal-Outcome Test - 22 (SNOT-22), Sniffin' Sticks Identification test and visuo-analogical scale, and the different timing of response, according to De Corso et al. criteria. RESULTS: Dupilumab treatment led to a progressive improvement for all outcomes at all time points. Comparing the different metabolic subgroups, a late response in terms of decrease in NPS was observed only in 3 obese patients. A significant decrease was also found in SNOT-22 score at 6 and 12 months, which was less marked in overweight/obese patients. CONCLUSIONS: Our study confirmed the efficacy of dupilumab in each BMI subgroup. However, the efficacy seems to follow different timing with respect to patients' BMI. Our data suggest that patients with a compromised metabolic state present more severe disease at baseline and a possibly delayed response to dupilumab.