An outbreak of Salmonella Agona linked to the consumption of infant formula (powdered milk) has been ongoing in France since August 2017. As of 11 January 2018, the outbreak had affected 39 infants (children <1 year of age): 37 in France, one in Spain confirmed by whole genome sequencing (WGS) and one in Greece, considered to be associated with this event based on the presence of a rare biochemical characteristic of the isolate. The date of symptom onset for the most recent case was 2 December 2017. Available evidence from epidemiological investigations in humans and traceability investigations in food identified seven different brands of infant formula from a single processing company in France as the vehicles of infection. After receiving the first notification on 2 December 2017 of an unusual number of S. Agona cases in France, the French authorities carried out investigations at the implicated factory. On 4 December 2017, they notified the Rapid Alert System for Food and Feed (RASFF) after confirming that some of the affected products were exported to other countries. Following investigations at the processing company, all products manufactured since 15 February 2017, including products other than infant formula, have been recalled and/or withdrawn, as a precautionary measure. The French competent authorities are verifying that the measures taken by the processing company in response to this event have been sufficient and appropriate. As of 15 January 2018, recalled products had been distributed to 13 European Union (EU) countries (Belgium, Bulgaria, Cyprus, the Czech Republic, France, Greece, Ireland, the Netherlands, Romania, Slovenia, Slovakia, Spain and the United Kingdom) and to 54 third countries. Most of the batches involved in the investigation have not yet passed their expiry date. However, broad withdrawal and/or recall measures, export bans and a suspension of market distribution of these batches, implemented since the beginning of December 2017 by the French competent authority and processing company A, are likely to significantly reduce the risk of human infection. The possibility remains, however, that new cases may be detected. Third countries, where the recalled products had been distributed, have been notified by RASFF through INFOSAN. ECDC offers WGS services to EU/EEA countries that do not have the capacity for a timely sequencing and analysis as part of this investigation. A multi-country WGS analysis is under way at the Pasteur Institute.