The nature of professional ethics of Finnish urban schoolteachers is explored. I argue that a high sense of professional ethics is one of the most important resources in maintaining hope and optimism in the challenging work of teaching. Ethical guidelines for the teaching profession which were established in Finland in 1998 now guide interactions between teachers, students, parents and colleagues. Four values are identified: human worth, honesty, justice and freedom. The empirical data were gathered from four urban schools with high national results and diverse populations. In narrative interviews of 12 teachers, challenges and rewards of teaching in the urban schools were discussed. Values and beliefs underlying teachers' professional ethics were identified, and some recommendations for teacher education were made.