This article presents a decision support methodology to assess potential locations for the new Hospital of Sintra (FHS), jointly with Hospital of Fernando da Fonseca (HFF), using Geographical System Information methodology and locationallocation models. The FHS will be a HFF complementary unit, sharing the same catchment area, i.e.,Sintra and Amadora Municipalities. The recent 203/2008 decree establishes the need of Sintras’ new hospital, defines HFF as a public hospital and creates Amadora-Sintra local health unit.