In conventional reliability-based optimum design of structures, the reliability is computed based on the probability assumption, and the design objective and constraint are considered as deterministic ones. In many cases, however, there exist some fuzzy factors in the design objective and constraint functions. In this paper, the fuzzy reliability and fuzzy constraint are introduced to establish the fuzzy reliability-based optimum model for laminated composites. The examples show that the method developed in this paper can give consideration to both the reliability demand and the economic aspect of a structure. Since the fuzzy reliability-based optimum design is a ’soft’ design, the present results provide a new methodology for the effective evaluation of structural reliability and bring us an alternative optimum design idea. In many reliability, based on the assumption assumption, and the design objective and constraint are considered as deterministic ones. There are some fuzzy factors in the design objective and constraint functions . In this paper, the fuzzy reliability and fuzzy constraint are introduced to establish the fuzzy reliability-based optimum model for laminated composites. The examples show that the method developed in paper paper can give consideration to both reliability of the economic aspect of a Since the fuzzy reliability-based optimum design is a ’soft’ design, the present results provide a new methodology for the effective evaluation of structural reliability and bring us an alternative optimum design idea.