Chronic spontaneous urticaria (CSU) has been associated with depression and can have an impact on quality of life. Therefore, researchers have suggested the potential utility of psychological interventions for targeting depression among CSU patients. Psychological interventions that may hold the most promise are those that are brief and easily transportable, such as brief behavioural activation treatment for depression. We report results of a preliminary investigation of an uncontrolled open trial of a one-session behavioural activation treatment for depression designed for patients with CSU (BATD-CSU) at a university-based allergy and immunology clinic. Participants were 11 females with chronic, poorly controlled urticaria and symptoms of depression. Following the completion of pretreatment questionnaires, participants were administered BATD-CSU primarily by non-mental health professionals trained and supervised in its delivery. One month post-BATD-CSU, participants completed follow-up questionnaires. Participants exhibited significant reductions in depression severity, avoidance/rumination, and work/school impairment. BATD-CSU was also associated with improvements in urticaria control one month post-treatment. Moreover, five of nine patients reported reliable and clinically significant improvement on at least one outcome. Results demonstrate that BATD-CSU may have benefits for CSU patients even when consisting of one session and delivered by professionals with limited background in psychological interventions, thus speaking to its feasibility and transportability.