Combination therapy, rotational therapy, and sequential therapy have been used for psoriasis in attempts to achieve greater efficacy and greater safety. The purpose of this manuscript is to review potential advantages and disadvantages of new biologic agents as we look forward to their use in combination regimens with other systemic, topical, and light therapies. Data on the efficacy and toxicity of existing systemic therapies and new biologic agents is reviewed with an emphasis on potential additive or synergistic benefits or toxicities. The mechanism of action of biologic agents differs from systemic agents currently in use, suggesting that there may be additive effects in treating psoriasis. The absence of hepatotoxicity and nephrotoxicity are important advantages when considering combination therapy with biologic agents. The advantages of the use of biologic therapies in combination or rotation with other systemic agents will have to be demonstrated in clinical trials. Mechanisms of action of the biologic therapies suggest that there is potential for additive benefit when used in combination regimens.