Research has examined the relationship of characteristics of crisis telephone workers to their performance. The influence and interaction of the characteristics of both the helper and caller on the telephone crisis intervention and outcome were explored for a sample of 59 calls to a crisis center. Data about the telephone helper (age, sex, experience at the Center, and professional/nonprofessional status) and caller (age, sex, problem area, crisis intensity, and repeater/non-repeater status) were obtained. Calls were monitored by trained observers who rated the calls on the Crisis Call Interaction Form and the Crisis Call Outcome Form. Findings revealed an interaction between the repeater status of the caller and the professional status of the helper. Helpers with professional training did not differ from non-professionals in the process and outcome of most calls, thus supporting the use of non-professionals. However, in calls involving repeaters, professional helpers engaged in less climate activity and more problem-solving activity; these calls were more successful on the affective dimension of resolution. The results indicate that repeat callers, dealing with long-term problems and difficulty in interpersonal relationships, benefit from professional helpers experienced in working with such problems. (NRB)