Following a request from the European Commission, EFSA was asked to deliver a scientific opinion on the safety and efficacy of sodium ferrocyanide and potassium ferrocyanide as technological feed additives for all animal species. In its previous opinion on the safety and efficacy of the additives, the FEEDAP Panel concluded that the use of sodium ferrocyanide and potassium ferrocyanide is safe, when added to sodium chloride at a maximum content of 80 mg ferrocyanide anions (anhydrous)/kg for turkeys for fattening and laying hens and other laying/breeding birds, all porcine species and categories, all ruminant species and categories, rabbits, horses, salmonids and other minor fin fish, dogs and cats. However, the Panel could not conclude on the safety of the additives for chickens for fattening and other poultry species for fattening or reared for laying/breeding other than turkeys, and for all species/categories other than the above listed. In the current assessment, the applicant is proposing a maximum content of 60 mg ferrocyanide anions (anhydrous)/kg sodium chloride for chickens for fattening and other poultry species (except turkeys) for fattening or reared for laying/breeding and for all species/categories other than the listed above. The FEEDAP Panel concluded that sodium ferrocyanide and potassium ferrocyanide are safe at a maximum content of 80 mg ferrocyanide anions (anhydrous)/kg sodium chloride for: turkeys for fattening and reared for breeding, laying hens and other laying/breeding birds, all porcine species, all ruminant species, rabbits, equines, salmonids and minor fin fish, dogs and cats. The Panel concluded also that a maximum content of 60 mg ferrocyanide anions (anhydrous)/kg sodium chloride is safe for chickens for fattening and minor poultry species for fattening or reared for laying/breeding and all other animal species.