Psoriasis is a common inflammatory and hyperproleferative skin disease characterized by infiltrated plaques of the skin and may involve nails, scalp and intertreginous areas. Recent years of research has shown that psoriasis can be treated topically with analogs of vitamin-D3. Impaired differentiation and increased proliferation of epidermal keratinocytes are key features in psoriatic lesions together with a local activation of T lymphocytes. Evidence has accumulated that analogs of vitamin D3 increase differentiation and inhibit proliferation of keratinocytes. Topical treatment with analogs of vitamin D3 have in a number of trials shown improvement of psoriasis. Vitamin D analogs show the same efficacy as potent topical corticosteroids and do not produce skin atrophy during long-term therapy. Vitamin D analogs can be used both as monotherapy and in combination with topical corticosteroids, UVB, PUVA, acitretin, methotrexate and cyclosporine. The vitamin D3 analog calcipotriol has been investigated in most detail and is available as an ointment, a cream and as a scalp solution. From clinical studies involving several thousands of patients, it can be concluded that calcipotriol is efficacious, safe and well-tolerated even on a long term basis.