This paper reports the fabrication of a biodegradable microfluidic device based on zein, a prolamin protein derived from corn. Micro-chambers and micro-channels features have been replicated on zein films using a stereo lithography master. Enclosed zein microfluidic devices are made by bonding the zein films with microfluidic features to glass substrates using a simple vapor-deposition method. The bonding strength of the zein microfluidic devices has been found to exceed hydraulic pressure, and fluid flow through large-area complex designs shows no leakage or distortion. High optical clarity and fluorescent imaging in the zein microfluidic devices are demonstrated by visualizing micro-particles and Rhodamine B. Zein-based devices enable truly disposable microfluidic devices with intrinsic biocompatibility and biodegradability that can be fabricated using conventional fabrication techniques. We intend to use the zein microfluidic devices in biological applications such as cell toxicity screening, cell culturing, and material absorptive applications.