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During the past two to three decades, significant progress has been made in estimating actual evapotranspiration using satellite remote sensing. Recently, the remote sensing and the techniques of geoprocessing have been used in diverse areas of research, mainly in environmental monitoring. The present study was intended to analyse the applicability of the SEBAL algorithm (Surface Energy Balance for Land) for energy balance estimation in the Brigida River basin, located in a semi-arid region of Brazil between 39 degrees 11'56 '' W longitude and 8 degrees 38'55 '' S latitude and 40 degrees 49'36 '' W longitude and 7 degrees 15'43 '' S latitude. Two TM - Landsat 5 images, orbit 217 and path 65, on 24 September 2009 and 16 July 1990, were processed, organized and analysed in a Geographical Information System (GIS) environment from which surface albedo, vegetation indexes (NDVI, SAVI and LAI), surface temperature, soil heat flux, and evapotranspiration were determined. The results showed that the reduction of vegetation cover is evident in the temporal and spatial analysis between the two periods. This reduction produced an increase of the temperature. The estimated evapotranspiration values were compared with the measured data at Araripina meteorological gauge. It was further observed that evapotranspiration increased gradually from 1990 to 2009, with an annual rate of about 10%. When comparing the mean annual evapotranspiration estimated from SEBAL and the observed data for each period, there is a satisfactory agreement.