This paper describes the methodology and results of classifications of multi-temporal Landsat TM/ETM+ data of the Prefecture of Thessaloniki, Macedonia Greece for the years 1986, 1999 and 2008. Nine different land cover/use categories have been used, named coniferous, broadleaves and mixed forest, agriculture lands, rangelands, grasslands, water bodies, urban areas and others uses. The overall classification accuracies were 85% for the three years, and the change detection accuracy was 88-91%. One of the most important results for the classifications is the fluctuation of the areas of the water bodies, mainly of the lakes, the decrease of the grasslands areas and the increase of forests, agricultural lands and rangelands. The results are being used to project future analyze landscape diversity and fragmentation, and examine different scenarios for more ecological management. The classifications have provided an economical and accurate way to quantify, map and analyze changes over time in land cover.