AbstractCeramic AlN nanoparticles were added to a melt of magnesium alloy Elektron21 assisted by mechanical stirring and sonication for deagglomeration. The produced nanocomposite was investigated to determine its metallography, hardness, physical and mechanical properties, and compression creep resistance. Creep tests at a constant temperature of 240 °C and constant stresses of between 70 and 200 MPa revealed an improvement in creep strength after the addition of 1 wt% of AlN nanoparticles. Minimum creep rates were determined and stress exponents were calculated. In order to determine the rate-controlling deformation mechanisms, the concept of a threshold stress for particle strengthened alloys was applied. True stress exponents were calculated for the alloy and for the composite.