In the study the microstructure and tribological behavior of a new magnesium matrix composite reinforced with glassy carbon particles (GCp) were presented. In the composite, obtained by powder sintering, the magnesium alloy AZ91 was applied as a matrix with 20wt% of particles of diameter approx. 100 m. The particle-matrix bonding was characterized by SEM with EDS, TEM with SADP, and nanoidentation tests. The main interest focused on the influence of GCp on the wear behavior of the composite. In the experiment sliding velocities of 0.06, 0.09 and 0.14 m/s, and loads of 2.3, 5 and 9.3 N were applied. The glassy carbon particle microstructure after sliding and the debris were characterized with SEM and EDS. The sliding wear test revealed that glassy carbon particles decreased the coefficient of friction for low load and sliding velocity. The mass lost of composite was very low and no destructive processes of the steel counterface were observed. During the sliding process, a mixture of oxidized AZ91E alloy and dispersed glassy carbon is formed between the composite and the steel counter.