The county of Rio Branco, similarly to the State Acre is establishing sustainable development strategies as the basis of the Program of Economic, Environmental, Social and Cultural Zoning of Rio Branco (Zeas). This program will lead to the production of the Map of Management of Rio Branco, in a 1:100.000 scale. In this study deforestation dynamics in the county was analyzed as a tool to support the decision making process in the establishment of public policies which reconcile economic development, creation of jobs, increase of income and social welfare and environmental conservation. The process of mapping deforestation was carried out by the Environmental Institute of Acre (Imac) using LandSat images from the year 1988 to 2007 with the support of ENVI 4.2 software. Rio Branco has an area of 2,377 km² of deforestation (27% of its total area) and a per capita index of deforestation fo 0.82 hectare. Deforestation is concentrated in the Eastern region of the county, around the urban area and along the federal highways BR-364, BR-317, the state highways AC-090 and AC-040 and the rivers margins. Between 2006 and 2007 there was a reduction of 58 km2 in the rate of deforestation. With the knowledge of the actual environmental, social, economic and cultural conditions it is possible to plan and carry out participatory programs aimed at reconciling the promotion of economic development, improvement of income and social welfare of the population and environmental conservation in the county of Rio Branco.