High dosage methotrexate is currently used in the treatment of malignancies. When used at low- or moderate doses, methotrexate has antiproliferative and antiinflammatory effects and is a useful drug in skin diseases. The aim of this review is to describe pharmacology, indications, adverse effects and practical use in Dermatology. Pharmacodynamics of methotrexate is especially related to antifolic activity. Methotrexate is officially approved in the treatment of severe psoriasis, but many other proliferative or inflammatory diseases with cutaneous manifestations may benefit from this drug, usually in association with corticosteroids. The use of methotrexate needs some precautions and a precise follow-up to minimise the risk of severe adverse effects. However, efficacy of methotrexate was reported in open and retrospective small size studies. Prospective and comparative trials are required to confirm the indications, advantages and tolerance of methotrexate in dermatology.