Investigators funded by the U.S. National Institutes of Health (NIH) under the Public Health Service (PHS) policy are required to receive conflict of interest training at a minimum frequency of every four years. Additionally, they must complete this training prior to engaging in research related to any PHS-funded grant or contract, and also immediately if the institution's policy changes in a way that affects the investigator or if the investigator is new to the institution or found non-compliant with the policy. This requirement ensures that investigators stay informed about conflict of interest policies and maintain ethical standards in their research. References to support this include NIH guidelines which require training before expenditure of funds for new awards, every four years thereafter, and immediately under designated circumstances; and institutional policies that mandate FCOI training at least once every four years.