Following a request from the European Commission, the EFSA Panel on Additives and products or Substances used in Animal Feed (FEEDAP) was asked to deliver a scientific opinion on the safety and efficacy of APSA PHYTAFEED ® 20,000 GR/L (6-phytase) as a feed additive for pigs for fattening. The additive is a preparation of 6-phytase produced by a genetically modified strain of Komagataella phaffii and has been previously assessed by the FEEDAP Panel in the context of three applications for its use in different species. The Panel concluded in those opinions that the production strain is safe, and that the use of the additive as a feed additive would raise no safety concerns for the consumers and the environment. The additive was also considered not to be irritant to skin or eyes or a dermal sensitiser but it should be considered as a respiratory sensitiser. The Panel considered that the new use in pigs for fattening would not modify the previously drawn conclusions with respect to the consumers, users and the environment. A tolerance trial in weaned piglets and a subchronic oral toxicity study were made available to support the safety for the new target species. From the results obtained, the Panel concluded that the additive is safe for pigs for fattening at the level of 1,000 U/kg feed. The applicant submitted three efficacy trials to support the efficacy of the additive. In two trials the apparent faecal digestibility of phosphorus and bone ash/phosphorus content were measured and in the third the effects on the performance of the animals were studied. The results of the studies submitted showed an improvement on the faecal digestibility of phosphorus in two trials, with no improvements on the bone mineralisation. Significant improvements on zootechnical parameters were found in the performance of pigs for fattening that were fed 1,000 U/kg feed in the long-term trial. Since significant effects in relevant parameters were found only in one trial the FEEDAP Panel could not conclude on the efficacy of the product in pigs for fattening.