BACKGROUND: The aim of this work is to define the chemical and mineralogical composition of the fuel gas desulphurization (FGD) gypsum produced from the Meliti thermal power plant in the region of Florina in North West Greece, in order to investigate potential uses in the cement industry. Mineralogical and microprobe analyses were carried out on FGD gypsum samples collected from the Meliti 330 MW lignite-fired power plant. RESULTS: Results show that the main component of the FGD gypsum is pure mineral gypsum (CaSO4.2H(2)O)The particle size of the gypsum ranges from 5 to 50 gm and the crystals are mainly of rhomboid shape. Microprobe analysis shows that the concentration of CaO and SO3, which are the main components, range from 31.9%-32.5% and from 45.90-46.40%, respectively. CONCLUSION: This FGD gypsum can easily substitute the natural gypsum used in the production of cement. (c) 2007 Society of Chemical Industry.