Clinical use of TNFα (tumor necrosis factor α) inhibitors, adalimumab and infliximab, for psoriasis began in January 2010 when an additional indication for this disease was approved. In January 2011, an interleukin-12/23 p40 (IL-12/23 p40) inhibitor, ustekinumab, was newly approved as the third biologic agent with an indication for psoriasis. All of these biologic agents are expected to exhibit excellent efficacy against not only psoriasis but also psoriatic arthritis, and to contribute to the improvement of quality of life (QOL) of psoriatic patients. At the same time, however, they require safety measures to prevent adverse drug reactions such as serious infections. We therefore decided to prepare this Guideline/Safety Manual for the Use of Biologic Agents in Psoriasis (The 2011 Version) by revising that for the use of TNFα Inhibitors prepared by the Biologics Review Committee of the Japanese Dermatological Association in February 2010. In this new unified version for all three biologic agents including ustekinumab, requirements for clinical facilities for the use of biologic agents, contents of safety measures against reactivation of tuberculosis and hepatitis B, and recommendable combination therapies with biologic agents, have been renewed and added. This guideline/safety manual has been prepared to assist dermatology specialists experienced in clinical practice of psoriasis to use biologic agents safely and properly.