CdSe was synthesized from an elemental mixture via a mechanically-induced self-propagating reaction (MSR). No reaction was observed in the induction period. When each elemental powder was separately pre-milled for 15 min, the elemental mixture formed CdSe after 5 s of milling, which is much shorter than that for MSR without the pre-milling process. It was thus deduced, that in the induction period, the mechanical energy supplied by the ball-milling process was employed primarily for activation of the particles. ZnSe was also formed via MSR from a pre-milled elemental mixture after 5 s of milling. The pre-milled Zn and Se powders showed lattice expansion, suggesting that the strain energy accumulated in the particles.