The Alcohol Program of the Spanish Network on Addictive Disorders-RTA requires a longitudinal study to address different research questions related to alcoholism. The cohort study (CohRTA) focuses on patients seeking treatment for alcohol use disorder, as a multicentre, collaborative research project aimed to improve secondary prevention and early diagnosis of pathological processes associated with the disorder. Methods: multicentre cohort study in adults (>18 years) seeking their first treatment of the disorder. Patients sign an informed consent and data is collected in an online platform specifically designed for the study; patients are also requested to provide biological samples that are stored in a biobank. Baseline and prospective, socio-demographic, epidemiological, clinical and treatment data are collected. Currently there are 10 participating centres that expect to recruit more than 1,000 patients. Results: As of December 2015, 344 patients (77% men) were included. Median age at admission was 50 years (IQR: 43-55 years). Median age at the start of alcohol consumption was 15 years (IQR: 14-18 years) and 61% of cases reported antecedents of alcohol use disorder in the family. During the 30 days prior to admission, alcohol consumption amounted to 12.5 SDU/day (IQR: 7.1-20 SDU/day), 72% of the patients were tobacco smokers and 30% currently used cocaine. Organising an open cohort of patients with alcohol use disorder may be crucial to better understand the clinical consequences of alcoholism in Spain. This cohort may potentiate quantitative and qualitative research within the Spanish Network on Addictive Disorders-RTA/RETICS. Having a well-established, representative cohort of patients will increase translational research on consequences of alcoholism in our country.