In this technical note an effort has been made to investigate the influence of flue gas conditioning, FGC, on physical, chemical, mineralogical and morphological characteristics of the fly ash. FGC is a technique that involves addition of chemical additives to the flue gas, for increasing the ash collection efficiency of electrostatic precipitators, ESPs. The FGC also helps in reducing the amount of suspended particulate matter, SPM, which is released into the surrounding environment at thermal power stations. It is a well established fact that utilization of the fly ash, as a cementitious material, depends on its pozzolanic characteristics, which in turn pivots on its physico-chemico-mineralogical and morphological characteristics. However, how these characteristics get influenced due to FGC has not yet been reported in the literature. With this in view, ash samples from a coal-fired thermal power station in India, where flue gas conditioning is being employed, were collected and their physico-chemico-mineralogical and morphological properties were examined. Based on these studies efforts have been made to highlight the influence of FGC on ash characteristics. (c) 2008 Elsevier Ltd. All rights reserved.