In the U. S. state of Arizona, schools have enrolled large numbers of Mexican immigrant and migrant students for a long time but the unprecedented migration of the last twenty years significantly increased pressure on Arizona teachers and teacher educators to deal with Mexican students in schools. Adding to this demographic pressure, the state severely restricted bilingual education programs and this resulted in placing Mexican migrant students with teachers who are not certified in bilingual education or in teaching English as a Second Language. Now, all teachers have Mexican migrant students in their classrooms and need to learn more about them and their prior school experience. The purpose of the qualitative study reported in this paper was to identify classroom practices in the Mexican state of Sonora bordering Arizona that could be useful to Arizona teachers teaching Mexican immigrant students. Data were collected from fifty-five classroom observations and teacher interviews in elementary and secondary schools during the 2008-09 academic year. Observation field notes included a daily running record of everything that happened in each of the fifty-five classrooms from the start of the school day to the end. Interviews with each teacher followed immediately and teachers explained what they did and why as well as talked about their goals, philosophy, and preparation for teaching. Findings reported here from the study which was funded by a Fulbright-Garcia Robles scholarship deal with instructional strategies, curriculum, resources, and general characteristics of the school day. The classroom itself was the unit of analysis and findings are presented as "points of contrast" between Sonoran classrooms and Arizona classrooms. This way of discussing differences between classrooms seemed to be a useful way of translating findings from the study into concrete recommendations for Arizona teachers working with Mexican immigrant students. Further, although the study was conducted to inform Arizona teachers, the presentation of comparisons between Sonoran and Arizona classrooms can also be useful to teachers in Sonora who are now receiving students returning to Mexico. In discussing findings from this Fulbright study with Arizona teachers, the more holistic approach of describing what Sonoran classrooms are like, what happens in the classroom, and what Mexican students are used to was more helpful than comparing specific instructional strategies or practices. This approach to analysis is important because few transnational comparative classroom studies are conducted from teachers' professional perspectives. Indeed, one issue related to comparative classroom research is that external researchers are often in the position of making recommendations for professional teachers without actually understanding their perspectives or daily work.