Professionals are often consulted to provide expert advice for topics a decision maker (client) lacks knowledge on. In many such instances, experts have a conflict of interest that may result in advice biased against their client’s objective. One commonly used method to address this problem in the field is mandatory disclosure of conflict of interests. This project provides experimental evidence on the potential beneficial effects of mandatory and voluntary disclosure of conflict of interests in long-term interactions. Our data shows that disclosure helps clients and hurts biased advisors. This is due to both lower exaggeration from biased advisors and higher deflation of advice from clients when the conflict is disclosed.