Based upon a belief revision model recently proposed by Einhorn and Hogarth, the present research investigates the effects of information presentation orders on tax professionals' belief revisions about ambiguous tax treatments. In particular, two dimensions of the tax professionals' beliefs are examined: judgment of tax treatment reasonableness, and recommendation of tax treatment to client. Also examined in the study are the impacts of the tax professionals' individual attitudes and the client's tax preference on the belief revision. The results show that both dimensions of the tax professionals' belief revisions are affected by the presentation order manipulations, but neither are affected by the client preference manipulations. The results also indicate that the tax professionals' individual attitudes affect their recommendations of the tax treatments to client, but do not affect their judgments of the tax treatments reasonableness.