BiOCl rectangular nanostructures with tetragonal phase have been successfully prepared via a sodium dodecyl sulphate (SDS)-assisted hydrothermal route using BiCl3 as Bi source material. The products were characterized by X-ray diffraction and scanning electron microscopy. The product exhibits regular rectangular structure with the length, width and thickness of 0.35-1 μm, 0.25-0.75 μm and about 80 nm, respectively. SDS plays an essential role on the formation of the BiOCl rectangular nanostructures. The formation of the BiOCl rectangular nanostructures can be controlled by adjusting hydrothermal temperature, time and SDS concentration. [DOI: 10.1380/ejssnt.2011.297]