Background The British Association of Dermatologists (BAD) established a web-based pharmacovigilance register to assess the long-term safety of biologics prescribed for patients with severe psoriasis in September 2007. The BAD Biologic Interventions Register (BADBIR) also participates in the network of European psoriasis biologics registers (Psonet). Objectives This prospective observational cohort study compares adult patients with psoriasis treated with biologics vs. a comparator group exposed to conventional systemic therapies. Methods Following baseline data acquisition, clinicians record changes in therapy, disease activity and adverse events for 5 years (6-monthly for 3 years, then annually thereafter). Patient details are flagged lifelong on the National Health Service Information Centre system to capture occurrence of malignancy or death. Primary study endpoints include malignancy, infection, serious adverse events and death. Collection of long-term effectiveness data is a subsidiary aim. Results By November 2011, the number of dermatology centres actively recruiting across the U.K. and Republic of Ireland had risen to 108 and a further 37 were actively engaged in the set-up process. Of the 3176 patients enrolled in the study to date, 2193 were registered within the biologic cohort and 983 in the conventional systemic (nonbiologic-exposed) cohort. Conclusions A robust, high-quality, web-based register of biologic and conventional therapy for psoriasis has been established in the U.K. This is the largest project undertaken by the BAD. The data it will provide over the coming years will be invaluable to the safe use of biologics in clinical practice. A U.K.-wide dermatology clinical research network has been established that provides a framework for future studies in other diseases.