Following a request from the European Commission, the EFSA Panel on Dietetic Products, Nutrition and Allergies (NDA) was asked to deliver an opinion on lacto-N-neotetraose as a novel food ingredient (NFI) submitted pursuant to Regulation (EC) No 258/97 of the European Parliament and of the Council, taking into account the comments and objections of a scientific nature raised by Member States. Lacto-N-neotetraose (LNnT) is a synthetic tetrasaccharide, which is intended to be used in infant and follow-on formulae, foods for special medical purposes for infants and young children and other foods for infants and young children, as well as in foods or food supplements for adults. The information provided on the potential mutagenicity of LNnT does not raise safety concerns as regards the genotoxicity of this NFI. Based on the observations from a sub-chronic 90-day toxicity study in rats, the Panel considers that the no observed adverse effect level is 2 500 mg/kg body weight per day. The applicant provided a double-blind, randomised, controlled clinical trial on the effects of LNnT consumed in combination with another oligosaccharide (2’-O-fucosyllactose (2’-FL)) in infants. The Panel concludes that LNnT is safe for infants (up to one year of age) when added to infant and follow-on formulae, in combination with 2’-FL, at concentrations up to 0.6 g/L of LNnT and up to 1.2 g/L of 2’-FL, at a ratio of 1:2 in the reconstituted formulae; is safe for young children (older than one year of age) when added to follow-on and young-child formulae, at concentrations up to 0.6 g/L of LNnT (alone or in combination with 2’-FL, at concentrations up to 1.2 g/L, at a ratio of 1:2). The Panel also concludes that LNnT is safe when added to other foods at the uses and use levels proposed by the applicant.