Unidirectional carbon-fiber/epoxy prepreg with embedded sacrificial fibers was manufactured and used to fabricate microvascular fiber-reinforced polymer (FRP) composites. A laboratory scale prepregger was designed and built for the continuous processing of resin impregnation, incorporation of sacrificial fibers, and fiber winding. The sacrificial fibers were annealed at elevated temperature during the prepregging process to obtain a good alignment with the neighboring carbon-fibers. A laminated FRP composite was manufactured from the prepreg by a hot-pressing technique. Sacrificial fibers from the separate lamina were fused due to the compaction and temperature of hot-pressing process. Three-dimensional microvascular networks were revealed within a laminated composite when the lattice of sacrificial fibers was vaporized at 200 °C. This is the first demonstration of multi-dimensional microvascular networks embedded within an FRP composite using a prepreg processing technique.