This study presents a statistical model for analyzing the reliability of a machining system considering a tool life distribution, as well as a statistical procedure for the design of a high-reliability machining system. Interruption of machining due to sudden tool failure or excessive tool wear is detrimental in automated machining systems. Not only does it disrupt production, but it also creates an obstacle in the construction of completely automated unmanned machining systems. High-reliability is a prerequisite for the design of an efficient and economical machining system. This study : ( 1 ) presents a new criterion (i. e., reliability criterion) for the design of a machining system, ( 2 ) defines the reliability of a machining system, ( 3 ) develops a statistical model to analyze the reliability of a machining system, and ( 4 ) presents a statistical procedure for the design of high-reliability machining systems.