This nationwide retrospective cohort study determined the association between alcohol use disorder (AUD) and the risk of necrotizing fasciitis (NF).This study used health insurance claims data of 52,212 in-patients with AUD and 208,848 controls randomly frequency-matched by age and sex at a 1:4 ratio. The AUD cohort included patients newly diagnosed with AUD between January 1, 2000 and December 31, 2008. The NF event occurrence was observed until December 31, 2011. We used the Kaplan–Meier method to present the cumulative incidence curve and Cox proportional hazard models to depict the risk of NF in patients with AUD.The incidence of NF was 19.4 per 10,000 person-years in the AUD cohort, which was nearly 7.73-fold higher than that in the comparison cohort (2.54 per 10,000 person-years). After adjustment for age, sex, and comorbidities, the patients with AUD exhibited a 3.55-fold higher risk of NF than did the controls (hazard ratio [HR] = 3.55, 95% confidence interval [CI] = 3.00–4.20). Nevertheless, in the AUD groups without any comorbidity, patients with AUD exhibited a significant 15.2-fold higher risk of NF than did the comparison cohort (HR = 15.2, 95% CI = 10.9–21.3). Moreover, the adjusted HRs of NF risk with respect to the severity of AUD were 2.15 (95% CI = 1.76–2.62), 4.54 (95% CI = 3.67–5.62), and 10.7 (95% CI = 8.66–13.2) for mild, moderate, and severe AUD, respectively.This study indicated that AUD should be considered an independent and significant risk factor for NF.