According to the Swedish school law parents have the right to choose if their child will join an ordinary class irrespectively of disabilities. In national and local guidelines for the Swedish school an important goal can be expressed as inclusion or inclusive education. As far as possible all pupils will have the right to join the nearest school and get the support they need in the ordinary school system in ordinary classes. In practice the situation for pupils in special needs varies between different communities, schools and classes. In my Ph.d. thesis (Jakobsson, 2002) I showed that ideology and regulations on different society levels as well as conditions in organisation and practice of the local school influenced how the school situation of the individual child was turned out. Other researchers have pointed to consequences of different teacher styles for the possibilities of pupils to participate in the lessons in the ordinary class.This paper deals with the daily work in classrooms and other arenas at school. In what ways can different pedagogical strategies in school practice contribute to inclusion or exclusion of pupils in special needs? What roles do attitudes, ways of working in the classroom, actions and co-operation in planning and carrying out the pedagogical work play? What incidents during the school day are crucial for the possibilities of participation and learning of all pupils and in what ways are they crucial? Such questions are analysed and discussed. The presentation builds on further and deeper analyses of data from earlier research, a special educational study of school situations of 50 pupils with different medical diagnoses (Jakobsson, 2002). The theoretical framework is connected to special educational, sociological and psycho-medical theories about diagnoses. It is an ethnographic study and data were mainly produced through partaking observations and interviews. Symbolic interactionism contributes to the understanding of what is going on and the analyses are conducted in an abductive and constant comparative process.According to the results of my earlier studies a number of critical incidents in the school practice were identified as crucial for the pupils' possibilities of participation and learning at school. The same incidents were critical all over the different school situations and the consequences could be connected to pedagogical strategies. The aim of the new analyses is to get deeper into the identified incidents and analyse them with inclusive and exclusive processes in focus. Identified critical incidents are presented and discussed on the basis of concrete examples of how different pedagogical strategies can be inclusive or exclusive.Jakobsson, I-L. (2002). Diagnos i skolan - En studie av skolsituationer för elever med syndromdiagnos. (Diagnosis at school - A study of school situations of pupils with a syndrome-diagnosis) (Göteborg Studies in Educational Sciences 185). Göteborg: Acta universitatis Gothoburgensis.