A silicon microstructured fiber has been designed and fabricated using a pure silica photonic bandgap guiding fiber as a 3D template for materials deposition. The resulting silicon fiber has a micron sized core but with a small core-cladding index contrast so that it only supports two guided modes. It will be shown that by using the microstructured template this fiber exhibits a number of similar guiding properties to the more traditional index guiding air-silica structures. The large mode areas and low optical losses measured for the silicon microstructured fiber demonstrate its potential to be integrated with existing fiber infrastructures.