Abstract: The IISE Code of Ethics is one of the few remaining engineering codes that does not explicitly address the obligations that members have to the environment. Given the range of complex environmental challenges faced in modern society and the critical role that industrial and systems engineers have to play with respect to solving these concerns, this omission is odd. This paper considers several philosophical arguments for and against the omission. These include arguments concerning the moral standing of the environment itself as well as the structure and function of a professional code of ethics. A key assertion here is that the omission of language concerning the environment is not a malicious one. Nevertheless, it is argued that the IISE Code of Ethics needs to be reevaluated and updated to include an explicit focus on the environment. After reviewing how other engineering codes of ethics handle environmental obligation, the paper concludes with suggested language and placement of this focus within the IISE Code.