A fuel cell system is provided including a fuel cell stack having a first end and second end; an upper end unit adjacent the first end of the fuel cell stack; a lower end unit adjacent the second end of the fuel cell stack; and a compression retention system disposed external to the fuel cell stack. The compression retention system includes at least one restraining member extending from the upper end unit to the lower end unit, fastening means disposed at opposite ends of the at least one restraining member, and compressive means interposed between at least one of the fastening means and the end units; wherein the fastening means and the compressive means urge the upper end unit toward the lower end unit, thereby applying compressive force to the fuel cell stack. Also provided is a method for assembling the fuel cell system.