Investment evaluation methods play an important role in today's competitive manufacturing environment. Shrinking profit margins and diversification require careful analysis of investments and decisions regarding these investments are crucial for the survival of the manufacturing industry. Both economic evaluation criterion and strategic criteria such as flexibility, quality improvement, which are not quantitative in nature, are considered for evaluation. Much has been written about the deficiencies of traditional models for justifying advanced manufacturing systems. The use of fuzzy set theory allows incorporating unquantifiable, incomplete and partially known information into the decision model. In this paper, an analytic hierarchical process (AHP) based on fuzzy numbers multi-attribute method is proposed for the evaluation and justification of an advanced manufacturing system. Finally, an example of machine tool selection is used to illustrate and validate the proposed approach.