Objective: We aimed to analyze sex differences in the DSM-5 criteria among patients admitted to their first treatment of alcohol use disorder (AUD). Methods: Assessment of AUD was carried out using DSM-5 diagnostic criteria in a multicenter study (CohRTA) within the Spanish Network on Addictive Disorders. Further, baseline questionnaires including socio-demographics, family history, lifetime alcohol consumption and other substance use, as well as clinical and laboratory parameters were obtained during admission. Results: 313 patients (74.8%M) were eligible; mean age at first AUD treatment was 48.8 years (standard deviation (SD): 9.9 years). Age at onset of alcohol use was 15.9 years (SD: 3.3 years) and age at starting regular alcohol consumption was 25.6 years (SD: 9.6 years). Almost 69.3% of patients were tobacco smokers and 61% had family history of AUD. Regarding other substance use, 7.7% were current cocaine users and 18.2% were cannabis users. Women started regular alcohol consumption later than men (p<.001) and used benzodiazepines more frequently (p=.013). According to DSM-5, 89.5% of cases had severe AUD (≥6 criteria). In the adjusted analysis (logistic regression), men were more likely to neglect major rules (OR=1.92, 95%CI: 1.06-3.48) and to have hazardous alcohol use (OR=3.00, 95%CI: 1.65-5.46). Discussion: DSM-5 detects sex differences in patients seeking their first AUD treatment. Social impairment and risky alcohol use are significantly more frequent in men.