In this thesis, a comparative life cycle assessment (LCA) of nuclear-based hydrogen and ammonia production is performed. Environmental impacts of nuclear hydrogen and ammonia production processes are assessed in five different impact categories selected from CML-2001 method. In one scenario BWR-HTE nuclear hydrogen production is compared with PWR-HTE nuclear hydrogen production to reveal the impact of nuclear power plant selection on LCA results. The LCA study of nuclear hydrogen and ammonia production methods is achieved by SimaPro software. Moreover, in the present study, a comparative cost analysis of various nuclear hydrogen production configurations is performed regarding hydrogen generation method, storage, and transportation of hydrogen, and nuclear power plant type. Hydrogen Energy Evaluation Program (HEEP) is utilized for cost analysis of various nuclear hydrogen production scenarios.