As a chronic disease psoriasis often requires long-term treatment. Successful continuation of therapy during a maintenance phase is therefore important. A systematic review was performed on the efficacy of psoriasis drugs during maintenance treatment in patients who had achieved sufficient treatment success during the induction period. Maintenance therapy is defined as treatment during the period after successful induction therapy. Inclusion criteria were prospective studies with systemic therapies recommended by the 2009 European psoriasis guidelines (plus ustekinumab), and a study population that had achieved a defined treatment response criterion after induction therapy within a period of ≥ 6 months. Maintenance studies on conventional treatments were identified for ciclosporin (CSA) only (no studies investigating acitretin, methotrexate or ustekinumab were found). Compared with placebo, CSA was shown to be effective in maintenance therapy, yet CSA 1·5 mg kg(-1) seems to be insufficient to maintain disease control. Based on the evidence, it is uncertain whether there is any difference between daily or intermittent treatment. For biologics, maintenance data were available for adalimumab, etanercept and infliximab. No differences in 75% improvement in Psoriasis Area and Severity Index (PASI 75) response were identified between adalimumab 40 mg once and twice a month. Continuous infliximab treatment was shown to be superior to as-needed treatment. For etanercept, only observational postrandomized controlled trial data were available, indicating a maintained PASI 75 response in approximately three-quarters of patients during long-term treatment. Only limited evidence is available for a conclusion on how patients with an adequate response should be optimally treated during the maintenance period. A clear ranking of the available treatments is not yet possible.