Bioregenerative Life Support Systems in the form of transparent, inflatable greenhouses present an economical and reliable solution for providing consumables to astronauts on long duration space missions. With NASA's goal to place human explorers on Mars, identification of cladding materials with appropriate optical and physical properties that can withstand the high ultraviolet radiation, low pressure, and low temperature Martian environment is necessary for greenhouse design. The objective of this study was to develop methods for evaluating the effects of simulated Mars environmental conditions on the transmissivity and mechanical strength of candidate greenhouse cladding materials. The University of Florida's Mars Simulation Chamber was utilized to expose material samples to simulated Mars environmental conditions. Changes in control versus exposed material sample transmissivities were measured using a spectroradiometer over a range of wavelengths from 200 to 800 not and material peak yield stresses were determined using an Instron universal testing machine. Results indicated that, under Mars simulated environmental conditions for 42 Mars equivalent days, materials experienced a reduction in transmission in the photosynthetically active region and a decrease in material strength. In short, the methods developed in this study provide a means for evaluating the transmissivity and strength of candidate greenhouse cladding materials under Mars environmental conditions for the determination of their suitability in greenhouse design.