This article presents a simple and novel method for the fabrication of cylindrical microchannels in polymer or biopolymer substrates. This process results in highly regular, cylindrical microchannels, suitable both to the transport of liquid and the transmission of light. This method eliminates issues associated with positioning tolerances characteristic of conventional fabrication techniques, such as soft lithography. Such devices hold great promise in the field of biomedical engineering by providing a true cylindrical profile for microflow studies and vascular modeling, as well as the ability to optically analyze injected biological samples. An evaluation of these devices is performed by real time optical imaging of blood flow.