A questionnaire survey was conducted with 106 in-service teacher education students of a university in Hong Kong to study their motives and commitment in teaching. Three motive factors were identified in their choice of teaching as a career, the most influential one is "intrinsic/altruistic motive", the next one is "extrinsic motive/job condition" and lastly "influence from others". Within the intrinsic/altruistic motive, around 80% to 95% teachers considered teaching is meaningful, they desired to teach the subjects they liked, they wished to help others and to work with children/teenagers. Four factors representing the areas or aspects of teaching which influenced the teachers' dedication and commitment were found, viz., "students' learning and school development", "demands on teaching and school practices", "teaching as a career choice", "teacher-pupils interaction and attitudes". Correlational analyses showed that intrinsic/altruistic motive was significantly related to the four commitment factors, suggesting that the motives held by the teachers in joining the teaching profession (in particular, intrinsic/altruistic motive) is influential upon teachers' commitment in teaching. Further analysis of the item responses highlights the elements affecting teachers' commitment in teaching involve school head, colleagues, students, parents and educational changes, which deserve the attention of the education authority to address with appropriate measures.