Abstract 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 the modification of the terms of the authorisation of OPTIPHOS® (6‐phytase) as a feed additive for pigs for fattening. The phytase present in this additive is produced by a genetically modified strain of Komagaetella pastoris(formerly known as Pichia pastoris). The additive is presented in solid and liquid forms and is authorised for use in avian species, weaned piglets, pigs for fattening and sows. The Panel issued an opinion on the safety and efficacy of OPTIPHOS® as a feed additive for avian and porcine species. This opinion considered the safety aspects of the additive with regard to the consumer, the user, the environment and the genetic modification of the production strain. The applicant seeks a modification of the terms of the authorisation for pigs for fattening, which consists in lowering the minimum recommended dose from 250 OTU/kg feed to 125 OTU/kg feed. Four trials were provided to support the efficacy of the product at the newly recommended dose. Three of these trials were balance trials and the results showed an increase in the retention of phosphorus in pigs for fattening fed diets supplemented with OPTIPHOS® at 125 OTU/kg. Therefore, the FEEDAP panel concluded that OPTIPHOS® has the potential to be efficacious in pigs for fattening at the new minimum recommended dose.