This work concerns the fabrication, modeling and characterization of a novel microfluidic flow sensor based on a microchannel capped with a porous silicon membrane, on top of which the sensor active elements are integrated. The microchannel is formed through a two-step anodization process. In the first step a mesoporous silicon layer is formed on a lithographically defined area, while in the second step a channel is formed underneath the porous layer by electropolishing. The channel is buried into bulk silicon and capped with a free-standing porous silicon layer, which is co-planar with the Si substrate. The overall developed process for the formation of the device will be described and simulation and device characterization results will be presented.