Following a request from the European Commission, the Panel on Additives and Products or Substances used in Animal Feed (FEEDAP) was asked to deliver a scientific opinion on l-tryptophan produced by fermentation using Escherichia coli KCCM 80152 when used as nutritional additive in feed and water for drinking for all animal species. The production strain and its recombinant DNA were not detected in the additive. l-Tryptophan, manufactured by fermentation with E. coli KCCM 80152, does not give rise to any safety concern with regard to the genetic modification of the production strain. The use of l-tryptophan produced using E. coli KCCM 80152 in supplementing feed to compensate for tryptophan deficiency in feedingstuffs is safe for non-ruminant target species. Using unprotected forms of tryptophan in ruminants can be a risk. The use of l-tryptophan produced by fermentation using E. coli KCCM 80152 in animal feed presents no concerns to consumers of animal products. Due to the content of endotoxins, the additive poses a risk for persons handling the additive when exposed by inhalation. The additive is not considered irritant for skin or eyes and is not considered a skin sensitiser. The additive under assessment is safe for the environment. The additive under assessment is regarded as an effective source of the amino acid l-tryptophan for all non-ruminant species. If l-tryptophan is intended for use in ruminants, it should be protected from ruminal degradation.