The importance of being able to decompose a large-scale engineering system into smaller subsystems which may be designed independently (yet concurrently) and integrated into a whole cannot be overemphasized. Many algorithms for the analysis of decomposed systems require that all variables, constraints, objectives and linkages between subsystems be precisely identified and rigorously specified. In practice, this extremely rigorous definition of the system and subsystems is often unattainable. The objective of this research is to develop a method of system analysis and synthesis based on the principles embodied in fuzzy set theory; a mathematical approach that has been developed to model imprecision rigorously. Specifically, the mathematics of fuzzy set theory will be incorporated into methods for hierarchical and non-hierarchical decomposition and resynthesis of problems. The resulting procedures will be integrated to provide a powerful tool for effecting the design of complex engineering systems through hierarchic and/or non-hierarchic decomposition in a fuzzy design environment.