The article presents the results of the petrographic analysis of the lignite from Turow deposit and the residues formed during its ex-situ gasification. The analysis used seven spot samples, representing different transformation areas, collected from the residues. The obtained results, compared with the lignite before the gasification, have shown that changes in the petrographic composition correspond to the temperature distribution during the process. The highest amounts of gasified particles, represented by inertoid-type chars, were observed in samples collected from areas where the temperature exceeded 600 degrees C. The unchanged lignite macerals dominated in samples from areas where the temperature was below 200 degrees C.