This paper relates an investigation of dentists' perceptions of their patients to a literature review of the interpersonal processes involved in professional helping. Although the concerns of dentists were markedly similar to those of other helping professionals there was a difference in priority possibly reflecting situational factors. The priority of the dentists' concerns were patient likeability, manageability and prognosis. It has been found that, for other helping professionals, four person-perception processes that occur in everyday life often lead to unfavourable perceptions of clients and work against the motivation to help them. Significant evidence of three of these four processes was found in the constructs described by the dentists. The three processes were: (a) attraction to similarity, (b) personalistic tendency in attributions, and (c) perceptual consequences of the patient's resistance to influence. The fourth process, a tendency to sample negative aspects of patients' behaviour, was not in evidence; on the contrary there was a significant tendency to sample positive aspects of the patients' behaviour by this sample of dentists.