Preliminary macro-petrographical analyses of samples taken from late Miocene (Pontian) to early Pliocene/Pleistocene lignite deposits at Achlada, northwestern Greece, show that there are two units in the lower 10 m of the lignite-bearing sequence. From 0 to 3.20 m a mixed xylite-rich /matrix lithotype is dominant and from 3.20 to 10 m a matrix-dominated lithotype is prevalent. The layers consist of organic and inorganic cyclical alternations with intercalated typical xylite horizons. The first results of coal petrographic analyses indicate a predominant huminite maceral group (60-81%) with a high content in liptinite (4-10%), and low in inertinite (0.2-2%). Plant association types revealed from palynological and seed and fruit analyses are open water, reedmoor, Taxodiaceae forest and mixed forest environments. Mineralogical research using X-ray diffraction (XRD), thermo-gravimetric (TG/DTG), differential thermal analysis (DTA), and Fourier Transform Infra Red (FT-IR) spectroscopy, shows that clay minerals prevail in all samples, with illite-muscovite being the dominant phase, followed by kaolinite and chlorite but with no smectite. The general area was a floodplain environment which included a large meandering river system