Psoriasis is a common, unpredictable, chronic immune-mediated disease characterised by skin lesions and frequently associated with arthritis. Although rarely fatal, psoriasis has a tremendous impact on a patients' quality of life. Traditional therapies for severe psoriasis include phototherapy, methotrexate, oral retinoids and cyclosporin. New biological agents add to the treatment options for psoriasis; however, they raise the already considerable cost of managing the disease. In considering efficacy, safety and cost-effectiveness, ultraviolet Type B (UVB) phototherapy appears to be the best first-line agent for the control of psoriasis. Methotrexate, psoralen plus UVA, alefacept, etanercept and infliximab are appropriate second-line agents, the choice of which requires considerable patient input and physician judgement. Developing rational, effective and acceptable strategies to manage psoriasis treatments would encourage cost-effective psoriasis management.