Psoriasis is a T-cell mediated skin disease that affects approximately 2% of the population worldwide. Despite the prevalence of the disease and long-standing efforts to develop strategies to treat it, there is a need for safe and effective therapies to treat psoriasis, particularly the more severe forms. Biological agents such as alefacept, efalizumab, etanercept, and infliximab have been recognized as a class of treatment distinct from other forms of therapy in the treatment algorithm of psoriasis. Recent national and international consensus meetings have developed statements that position biological agents as an important addition to the treatment armamentarium for moderate to severe psoriasis, along with phototherapy and traditional systemic agents. There has been consensus that treatment should be individualized to each patient's needs and circumstances. Biological agents offer the hope of safe, effective, long-term management of moderate to severe psoriasis. As new agents receive approval from Health Canada, the available range of therapeutic options for treating this chronic disease will broaden. A Canadian Psoriasis Expert Panel recently convened in February 2005 to analyze, based on a series of clinical case scenarios, the indications, contraindications, and considerations for and against each of the four biological agents, derived from product labelling, where available, and from the efficacy and safety data from phase 3 and earlier clinical trials, as well as post-marketing reports. The Panel has formulated a set of recommendations for incorporating these biological agents into the current treatment paradigm of moderate to severe plaque psoriasis and has identified the preferred biological agents for each patient based on individual needs and circumstances.