Magnesium hydroxide Mg(OH)(2) nanoneedles with diameters of 40-60 nm and lengths of more than 650 nm have been fabricated by a fast and safe route in de-ionized water. X-ray diffraction (XRD) showed that the Mg(OH)(2) nanoneedles were well-crystallized with the hexagonal structure, whereas from the morphological investigations using scanning electron microscope (SEM), it was revealed that the nanoneedles are grown in a very high density over the whole foil substrate. The structure features were also analyzed by high similar to resolution transmission electron microscopy (TEM). The approach is based on a simple reaction of magnesium foil and de-ionized water without using surfactants. The reaction time is 3 h and the temperature is similar to 110 degrees C. The advantages of producing nanoneedles using this method include ease, flexibility, speed, and cost. The process can easily be scaled up.