An experimental study of the main parameters affecting Greek lignite – CO2 gasification, as well as an evaluation of kinetic models, appropriate for lignite gasification, are discussed. Gasification tests were conducted in a fixed bed reactor operating at ambient pressure. Parameters investigated were (a) gasification temperature (750 – 900°C) and time (1 – 50 min), (b) CO2 partial pressure (0 – 1 atm) and (c) particle size (106 – 1000 ėm). Lignite porous structure was analysed by CO2 and N2 adsorption at 298 K and 77 K respectively. Results show that Ptolemais lignite is quite reactive with CO2, resulting in high conversions even at short reaction times. For the granulometries studied (up to 1000 ėm) the gasification rate is independent of particle size, indicating that lignite – CO2 reaction takes place homogeneously. Weight loss increases with temperature due to both pyrolysis and C – CO2 reactions. Thus, a ~50% conversion increase is observed, by increasing the gasification temperature from 750°C to 900°C. An increase of lignite conversion with reaction time indicates that lignite chars remain reactive with CO2 after devolatilisation. However, gasification rates decline after 10 – 20 min of reaction, since carbonaceous material tends to be completely consumed. CO2 partial pressure affects the gasification rate, especially at low CO2 partial pressures. The reactivity of lignite remains high (conversion ~85% w/w daf) even for 0.25 atm CO2 partial pressure. Porous structure analysis shows an initial increase in porosity characteristics (surface area, pore volume and pore size distribution) and a subsequent decrease at high lignite conversions (> 80% w/w) due to consumption of the carbonaceous material and/or pore closure. The experimental kinetic parameters were compared with estimated values based on the volume reaction, the unreacted core and the deactivation models. The activation energy was found to vary with time, due to the different nature of carbon atoms gasified as the gasification reactions proceeds