The aim of this study is to analyse the efficacy of a trans-diagnostic psychological therapy group aimed at reducing anxiety symptomatology. This was delivered within a Primary Care setting by clinical psychology. The assessment was completed through the outcome measure Clinical Outcomes in Routine Evaluation-Short Form A (CORE-SFA). The intervention consisted of a Cognitive Behavioural Therapy group that delivered one session a week for 4 weeks. Components of this therapy included: psycho-education, cognitive restructuring, assertiveness training, sleep hygiene, problem solving, relaxation techniques, and time management. The data for this study was collected between January 2015 and October 2016, with a sample of 48 patients. Results from the data collected demonstrated a statistically significant reduction of the anxiety symptomatology. Moreover, 79.2% of the sample was discharged from services following this group intervention. The clinical implications of this study are discussed, supporting the efficacy of a trans-diagnostic Cognitive Behavioural Therapy group in a Primary Care setting for the treatment of symptoms of sub-clinical anxiety and depression. Copyright © 2018 Sociedad Española de Médicos de Atención Primaria (SEMERGEN). Publicado por Elsevier España, S.L.U. All rights reserved.