Mixtures of zirconium and carbon powders in various atomic fractions (5-75 at.% of C) were ground in a planetary ball mill. When the mixtures thus activated mechanically were transferred into a graphite crucible and exposed to air, they ignited spontaneously and the self-propagating high-temperature synthesis (SHS) took place in two successive steps, Zirconium carbide and zirconium nitride were formed, depending on the initial C concentration. The almost stoichiometric ZrC was formed in air from the Zr-C powder mixtures with C = 50-60 at.%. From the measurement of the lattice constant and X-ray photoelectron spectroscopy (XPS) spectra, the formation of solid solutions between ZrC and ZrN was also estimated. A possible reaction mechanism for the formation of the zirconium carbide and nitride is discussed.