This paper looks at how cooperating teachers and student teachers interact and the effects, if any, on the student teacher. The study explored the cases of three student teachers and their cooperating teachers, focusing on whether the student teachers appeared to experience any positive or negative effects as a result of a matched pairing placement or a mismatched pairing placement with regard to their theoretical orientation to the reading process. Potential pairs for the study were identified through Theoretical Orientation to Reading Profile (TORP) scores; student teachers and cooperating teachers were not purposely matched or mismatched. Data from the study were used to glean student teachers' perceptions of their student-teaching experiences, which were then viewed in relation to their matched or mismatched pairing placements. Although Pair One held dramatically-opposed theoretical orientations to the reading process, with no overlap, their mismatched pairing placement did not produce negative effects in the student teacher; in fact, it produced positive effects due to the personality traits of the cooperating teacher. Pair Two appeared to be in perfect harmony throughout the student teaching experience; positive effects in this case were due to both theoretical orientation similarity and the personality traits of the cooperating teacher. Pair Three held dramatically opposed theoretical orientations to the reading process with no possible overlap, as well as dissimilar attitudes, understanding, focus, and expectations. In this case, the student teacher was displeased with the placement and felt that the cooperating teacher did not offer positive support. Findings of the study revealed that certain personality traits of cooperating teachers, in addition to belief systems or theoretical orientation, appear to be important factors in determining whether student teachers perceived their student teaching placements to be negative or positive. (Contains 10 references.) (ND)