This paper presents the existence of sunk costs effect in the process of ISO standards development, as well as to highlight their influence in the direction (draft writing) and outcome (vote) of these processes. Our field of study was the ISO 26000 standard development (which required ten years of work to finalize.) This paper sheds new light on standardization, which increasingly influences management practices, because it pays particular attention to a concept developed in experimental economics and tries to link this with other costs concepts developed in management.