Studies on the radiation balance in areas of agricultural expansion, especially in agro-exporting states such as Mato Grosso, are relevant to understanding the atmosphere-biosphere interaction. This study estimated some components of the radiation balance in different areas (secondary forest, reforestation with eucalyptus trees and agricultural crops) in the city of Lucas do Rio Verde/MT using Landsat 5 - TM images. The images chosen were acquired on January 20 and April 26 of 2010. The images were processed using the SEBAL algorithm to calculate the values of the instantaneous radiation balance (Rn inst), albedo and NDVI. The results showed high variability of Rn inst, albedo and NDVI considering both different coverages and dates. The areas of secondary forest and reforestation of eucalyptus showed similar magnitudes, while areas with agricultural crops had values with intrinsic relations for the stages of development with complex radiative interaction.