The modification of wood with methylolated melamine formaldehyde resin (MMF) belongs to the group of impregnation modifications. In the course of this study, Koto sapwood samples were impregnated with MMF-solutions in a full-cell vacuum-pressure process. The samples were cured at a maximum temperature of 120 ºC for 24 hours. To characterize the modification, the solution uptake (SU) and weight percent gain (WPG) of the samples were calculated. The fixation of the melamine as parameter for the degree of curing was examined by C/N analysis. Areal UV-microspectrophotometry (UMSP)-scans of ultra-thin transverse sections of an untreated control and MMFmodified samples at 240 nm were recorded. Additionally, photometric point measurements with a spot size of 1 μm2 in the range 230 nm and 350 nm were conducted. UMSP was proven as suitable technique for the quantitative analysis of MMF-modified wood.