This study aimed at monitoring,mapping and assessing the sand dune encroachment in the northern central part of Iraq.The study area includes six districts suffer from the increasing prevalence of sand dunes,particularly in the recent years which characterized by dry weather and a reduction in rainfall averages.Remote sensing “RS” and in particular,Earth observation satellites besides Geographical Information Systems “GIS” provide significant contributions to sand dunes encroachment monitoring.Two Landsat TM images acquired in July of 1988,and July of 2009 were assembled and used to extract the research indices.Satellite image based indices; the Normalized Difference Vegetation Index “NDVI”,the Tasseled Cap Wetness Indicator “TCW”,the Land Surface Temperature “LST”,and the Normalized Difference Sand Index “NDSI” (a new index which has been proposed in this study) with RS and GIS techniques were used for monitoring the sand dune encroachment at two sites in the northern central part of Iraq.The results of this study showed an increase in the sand dunes accumulations by 2,020.6 km2 and 291.1 km2 throughout the 21 years from 1988 to 2009 in Baiji and Al-Aith sites in the region,respectively.Sand dunes movement rates for the same period were 1,155.9 m year-1 and 494.2 m year-1 in the two mentioned sites,respectively.The results showed that the study area in general is exposed to a high risk of sand dune encroachment.The use of soil conditioners and windbreaks has been proposed to mitigate the impact of sand dune encroachment in the study area.