Professional auditors participated in four belief-revision experiments that examined the differential responsiveness of their revisions to positive and negative evidence and the impact of presentation mode on their revisions. In two auditing and two nonauditing tasks, the auditors were more responsive to negative than to positive evidence, and revised their beliefs to a greater extent with sequential than with simultaneous evidence presentation. We argue that important aspects of the education and training of auditors, and of the legal and professional environment in which they work, may be expected to distinguish their approach to evidence evaluation from that of other groups. This argument is supported by two additional experiments which show that another group of professional subjects (business executives) do not exhibit direction-of-evidence and presentation-mode effects in the same nonauditing tasks. Implications for belief revision in professional settings and directions for further research are discussed. © 1990.