The significance of corrosion of nickel-titanium instruments is controversial. There are still insufficient data on the clinical influence of the fracture behaviour of instruments. Impressive pictures of instruments that have been destroyed after being stored in sodium hypochlorite have been published, but this destruction is rarely seen clinically. This article provides a brief overview of the corrosion of nickel-titanium instruments. Keywords: corrosion, fracture, NaOCl, nickel-titanium, preparation