The DOJ Tax Division has long recognized the efficacy of parallel criminal and civil proceedings and actively pursues them in its current endeavor at increased enforcement. Parallel proceedings often present complicated issues that create additional challenges for taxpayers and their attorneys. When a parallel proceeding is pending, the invocation of the Fifth Amendment by either the taxpayer, a tax advisor, or other non-party witness can create adverse implications in a subsequent proceeding. Taxpayers and their attorneys must carefully navigate the risk of an adverse inference against the taxpayer under the circumstances of the particular case. The well-informed attorney can prepare to face all of these issues and effectively navigate the specific facts of his or her case. The following discussion will explain and analyze: the effect of a party’s invocation in independent proceedings, the effect of a party’s invocation in parallel proceedings, the implications of a non-party’s invocation, and whether an invoker can waive the privilege and later testify.