Graduation thesis deals with a possible use of liquefied poplar wood for impregnation of solid poplar wood. Liquefied poplar wood was modified with formulations containing different concentrations of the melamine resin called Melapret NF70/M (MF). At first, the optimal curing temperature and time were determined. Then the cured mixture was tested for its surface hardness, elasticity and surface resistance to cold liquids. On the basis of these test results, we selected 2 representative mixtures: 1st with a lower concentration of MF and 2nd with a higher content of MF. These 2 mixtures were used for impregnation of poplar wood. We used the full cell treatment procedure also known as the Bethell schedule. After impregnation, the dimensions and weight of the samples were measured and the resin solution retention (MN) determined. The impregnated samples were then dried under similar conditions as the mixture before. After curing and drying the samples to their absolutely dry state, the dimensions and masses were measured again, and solid resin retention (SN) and weight percent gain (WPG) determined. To determine how well the mixture set and bonded into the cell walls we were soaking the samples in water to become completely wet. After the soaking process, anti swelling efficiency (ASE), water retention (S) and water repellency effectiveness (WRE) were measured. Afterwards the specimens were dried to their absolutely dry state. The percentage of leached-out mixture was determined by mass loss of the samples. Presuming that the only substance that leached out of the impregnated wood was the liquefied wood, we calculated the percentage of the leached liquefied wood. The results showed that the samples, impregnated with the lower concentration mixture, had higher mass losses after soaking than the samples, impregnated with the mixture of the higher concentration. ASE of the samples was the same for both mixtures and was just slightly lower than ASE of untreated samples. ASE of the treated samples, compared to the ASE of the untreated ones, showed that the mixture is not effective in water sorption prevention. Liquefied wood in combination with melamine resins is a fairly new material, and up to our best knowledge it has not yet been reported in the literature. Its use for saturation of wood did not prove well by our results. But the material has a large potential in research and development of new plastic and wood-based materials. For better understanding of such materials a lot of research still has to be done.