Intensive research on optical interconnection over flexible optical circuit boards has been undertaken for such applications as high-end routers, servers and cellular phones. And these flexible optical circuit boards are expected to be used for polymer optical waveguides. This paper reports recent progress on polymer optical waveguides. It also describes a flexible stamping method, which employs a flexible film stamp made of polymeric materials. Unlike conventional hard stamps, the flexible film stamp does not require either the stamp or its substrate to be perfectly flat, which means large area stamping is easy to achieve at reduced cost. We confirmed this by replicating 50 μm multi-mode optical polymer waveguides. The propagation loss of the waveguide is fairly low at 0.06 dB/cm at a wavelength of 850 nm. This loss is sufficiently small to meet the basic requirement for optical circuit boards, and the waveguide was used to fabricate a flexible optical circuit board with MT connectors.