Tick-borne encephalitis (TBE) is described in Switzerland since 1969. More than 200 cases are reported every year to the Federal office of public health (FOPH) and new sites of endemic disease have been documented recently, in particular in the North part of the canton de Vaud. The aim of this article is to review the clinical pictures of 11 patients hospitalised in Yverdon-les-Bains with a diagnosis of TBE between 2003 and August 2007. The occurrence of 5 new cases exposed in the North part of the canton de Vaud over these last 18 months confirms the presence of endemic foci in this area and should prompt the vaccination against the MEVE which is recommended by the FOPH in endemic zones. The sequels of MEVE being observed mainly in the elderly, vaccination should be afforded also to this group of patients.