Following a request from the European Commission, the Panel on Food Additives and Nutrient Sources added to Food (ANS) was asked to deliver a scientific opinion on microcrystalline wax (E 905) when used as a food additive. Microcrystalline wax (E 905) is authorised quantum satis as a surface treatment agent on non-chocolate confectionery, chewing gum and decorations, coatings and fillings, except fruit based fillings. It is also permitted as a surface treatment of melons, papaya, mango and avocado. The substance was evaluated by the Scientific Committee on Food (SCF) in 1990 and 1995 and by the Joint FAO/WHO Expert Committee on Food Additives (JECFA), the latest in 1995. The JECFA established a group ADI of 20 mg/kg bw/day for mineral oils, paraffins and microcrystalline waxes. The Panel noted that all mineral oil products accumulated in tissues in a dose- and time-dependent manner with the exception of microcrystalline waxes. The Panel concluded that there is no concern for genotoxicity from microcrystalline wax (E 905). The Panel also considered that the available toxicity studies with mineral hydrocarbons, closely related from a chemical point of view with microcrystalline waxes, consistently reported no effects of concern associated with the intake of microcrystalline wax. The Panel further concluded that since no long-term toxicity and carcinogenicity studies with microcrystalline wax E 905 were available, no ADI could be established. The Panel also concluded that the conservative exposure estimates to microcrystalline wax (E 905) from its use at maximum permitted level (following quantum satis rules), resulted in a sufficient margin of safety compared to the NOAEL established by the Panel for the closely related high viscosity mineral oils, and therefore the use microcrystalline wax (E 905) as a food additive with the currently authorised uses would not be of safety concern.