A high percentage of patients have a diagnosis of adjustment disorder (AD) when they arrive at primary care (PC) appointments. However, most of them do not receive adequate psychological treatment. The present study’s aim is to determine the efficacy of a group psychological treatment program in patients with AD. The sample consisted of patients with AD from two PC units in Valencia, from which two groups were randomly generated: A treatment group (n = 31) and a waiting-list group (n = 20), homogeneous in terms of socio-demographic and psychometric variables prior to treatment. Treatment consisted of eight one-hour group sessions held on a weekly basis; taking a cognitive-behavioral approach, they addressed aspects like controlling anxiety, cognitive restructuring, and coping techniques. The variables analyzed were: Psychopathology (Revised Symptom Inventory, SCL–90–R), health-related quality of life (Health Questionnaire, SF–12), and risk of suicidal behavior (Suicide Risk Scale). Means comparisons, ANCOVAs, and tests of effect size were performed. Statistically significant differences were observed in the variables, such that after intervention, the experimental group exhibited less anxious (F = 4.11, p =.048, η2 = .08) and depressive symptoms (F = 2.41, p =.029, η 2= .10) and higher quality of life related to physical (F = 7.17, p =.010, η2 = .13) and emotional health (F = 10.31, p =.002, η2 = .18). For the reasons above, we conclude that a comprehensive approach to emotional distress in PC, including group psychological interventions, is one solution for the demand for social services, and could provide savings on economic as well as human costs.