Nickel nanocrystallites with hexagonal flake-like morphology with a side length of 200-400 nm and a thickness of 20-30 nm were prepared by reduction of nickel dimethylglyoximate with hydrazine hydrate in a solution. Selected area electron diffraction (SAED) pattern revealed that the flakes were single crystals. It was found that the precursor, nickel dimethylglyoximate, played an important role for the formation of these flakes. Magnetic properties of the product were measured by a vibration sample magnetometer (VSM).