The work sought to investigate the implementation of public policies of special education in the municipal system of Corumbá / MS based on the perceptions of the implementing agents. As specific objectives, we wanted to learn how educational policies aimed at students with disabilities are implemented in the municipality and what the conditions of attendance of these students are in the municipal system. We focused particularly on the interaction between the school board with the Municipal Department of Education, and the way the service to the disability students is provided considering the operation of the school management and teachers. As a theoretical framework, we use studies on middle-level and street-level bureaucracy to understand how these relationships are established. We also used the literature on the historical context of special education policies to understand how they were consolidated in Brazilian society, in addition to Disability Studies, which offered us keys to interpret phenomena through the sociological perspective of disability, especially throughout the Ableism concept. Initially a survey was applied to the management teams and teachers of all urban schools of the municipal system of Corumbá, summing sixteen school units. From the analysis of data collected and the microdata of the 2016 Brazilian School Census, three schools were chosen to participate in a following movement of qualitative research. This qualitative phase included about a month of observation of the daily life in each school and semi- structured interviews done with eight members of the management team and ten teachers. This second phase of research was than complemented with official documents analysis and six semi-structured interviews with professionals from the Municipal Education Department. The results showed that the agents implementing the policies of the special education, despite their efforts to carry out the work, find difficulties that interfere directly in their work. The precarious functioning of some school units, the pressure to hold the principals accountable for the school results, without the provision of adequate work conditions, and the dismantling in the last years of the educational team responsible to provide the service to the students with deficiency of the municipal system, are factors that impact the work of the professionals at school level. In addition to that we highlighted the perceptions of the implementing agents to the concept of disability and the fact of the majority of them considers disability students as unable. This set of factors contributes to the results found in the School Census that show that these students, although they attend the regular school, within the framework of the current policy of educational inclusion, are mostly retained in the initial years of Elementary Education, rarely completing the conditions for effective school and social inclusion.