Motion to Disqualify Counsel Ohio
Ohio has two different approaches to motions to disqualify counsel.
These approaches depend on whether the case is one of successive representation or simultaneous representation.
In some respects a trial court must engage in similar analysis under both approaches; in other respects the analysis differs.
 In both successive and simultaneous representation cases there is a rebuttable presumption that disclosure of confidences has taken place. Sarbey v. Natl. City Bank, Akron (1990), 66 Ohio App. 3d 18, 26-27, 583 N.E.2d 392, 397-399.
 Once an attorney-client relationship has been established, the determination of whether a conflict of interest exists by virtue of adverse representation depends on whether confidential information was imparted during the attorney-client relationship, and whether there is a threat of improper use of that information in violation of DR 4-101 through the adverse representation. Id. at 26, 583 N.E.2d at 398.
 the primary purpose behind the prohibition in DR 5-105 against dual representation of clients with adverse interests is to ensure that confidences or secrets of a client imparted to an attorney in the course of their attorney-client relationship will not be revealed to an adverse party or used to the client's disadvantage. Id.
 If the disqualification motion concerns successive representation, then the burden of proof is on the client to show that there is a substantial relationship between the subject matter of a former representation and that of a subsequent adverse representation. Id. at 23, 583 N.E.2d at 396.
 If the disqualification motion concerns simultaneous representation, then courts do not apply the "substantial relationship test." Id. at 24, 583 N.E.2d at 396.
 Simultaneous representation is prima facie improper, and an attorney who is seeking to sue a present client must show that there is no actual or apparent conflict of loyalties or diminution of vigor in his or her representation. Id.
 Disqualification of an attorney in a successive representation case is granted only when representation poses a significant risk of a violation of the Code of Professional Responsibility. Henry Filters, Inc. v. Peabody Barnes, Inc. (1992), 82 Ohio App. 3d 255, 259, 611 N.E.2d 873, 875.
 In a successive representation case the moving party must show that disqualification is absolutely necessary to counter the significant risk of a violation of the Code of Professional Responsibility. Phillips v. Haidet (1997), 119 Ohio App. 3d 322, 324, 695 N.E.2d 292, 293-294.
In a successive representation case the moving party must show that the trial will be tainted. Id. at 327, 695 N.E.2d at 295-296.
DR 5-105(C) allows for simultaneous representation only in narrow circumstances: if it is obvious that the attorney can adequately represent both interests, and if each client consents to such representation after full disclosure of the possible effect of such representation. Sarbey at 29, 583 N.E.2d at 400.
Evidence that supports the existence of an attorney-client relationship will vary from case to case. Henry Filters, 82 Ohio App. 3d at 261, 611 N.E.2d at 876-877.
 the ultimate issue is whether the putative client reasonably believed that the relationship existed and that the attorney would therefore advance the interests of the putative client. Id.