Acute compartment syndrome of an extremity poses a threat to both life and limb. The usual cause in children is trauma, especially fractures and burns. Two recent cases of nontraumatic compartment syndrome of the extremities in children are presented, both owing to infection followed by myositis or fasciitis. Both cases required urgent decompression by fasciotomy, resulting in limb salvage and full recovery of neuromuscular function of the extremity. The value of prompt recognition and treatment of this condition is emphasized.