A judge may be disqualified from hearing or presiding over a matter in which provable facts suggest the judge has a disqualifying conflict of interest. The related legal process of recusal of a judge is generally based on the perception of impartiality due to circumstances that suggest a conflict of interest—but not to the same degree as the facts that establish disqualification.

The standards for disqualification of a judge vary from state to state, and disqualification is rare. But a judge is generally disqualified in any proceeding in which:

(1) the judge has served as a lawyer in the matter in controversy, or a lawyer with whom the judge previously practiced law served during such association as a lawyer concerning the matter;

(2) the judge knows that, individually or as a fiduciary, the judge has an interest in the subject matter in controversy; or

(3) either of the parties may be related to the judge by affinity or consanguinity within the third degree.

In Iowa, a judge may be disqualified from presiding over a case if there are provable facts indicating a conflict of interest that could affect the judge's impartiality. According to Iowa Code Section 602.1606, a judge is disqualified from a proceeding if they have previously served as a lawyer in the matter, if they have a personal or fiduciary interest in the subject matter of the controversy, or if they are related to a party within the third degree of affinity or consanguinity. The process of a judge stepping down from a case due to potential bias or conflict of interest is known as recusal. While disqualification is relatively rare, it is a crucial aspect of ensuring fairness and impartiality in the legal process. If a party believes a judge should be disqualified, they can file a motion for recusal, and the judge has the responsibility to determine whether their involvement would violate the standards of impartiality required by law.