Purpose: There is little understanding of how physical therapy students are influenced by clinical instructors (CIs) particularly at the outset of their clinical learning. The purpose of this study was to evaluate physical therapy students' perceptions of their learning experiences during an introductory clinical placement. Methods: Subjects were 51 physical therapy students participating in an introductory clinical placement following the first unit (semester) of a 2-year, entry-level Master's program. Each day of their placement, students completed a questionnaire based on Brookfield's Critical Incident Questionnaire. Students were asked when they felt most engaged or distanced, what actions of others were most affirming or puzzling, and what surprised them about the placement that day. Two evaluators independently read and coded the entries in all questionnaires, and then collaborated to establish themes related to the behaviors of the CI. Results: The CI could enrich the students' experiences in the following ways: (1) prepare them by introducing, explaining, demonstrating, or allowing them time to obtain information. (2) Confirm learning by providing feedback and recapping. (3) Provide "hands on" experiences appropriate to students' knowledge, skills and comfort. (4) Challenge students by questioning, discussing possibilities, or providing time for reflection. (5) Respect students, value their input and allow them an appropriate level of independence. (6) Demonstrate professional behavior related to communication, evidence-based practice and continuing education. Conclusions: Physical therapy students value CIs who involve them in patient care; confirm, challenge and prepare them for learning; respect their input and model professional behavior.