This article reports on the design and development of two fiber optic sensing systems that facilitate the cure monitoring of an epoxy/amine thermoset in a microwave oven. First, the design, construction, and evaluation of a fiber optic probe were necessary so that noncontact diffuse reflectance spectra could be obtained during the curing of the resin in a microwave oven. Second, a low-cost, disposable fiber optic temperature sensor had to be developed for use in the microwave oven because the use of conventional metal-based thermocouples was not possible. The deployment of the two sensor systems was demonstrated successfully. (C) 2003 Wiley Periodicals, Inc.