The US FDA has withdrawn emergency-use authorization for tixagevimab and cilgavimab because of a lack of efficacy against some strains of SARS-CoV-2. These drugs are monoclonal antibodies directed against the SARS-CoV-2 virus that causes COVID-19 and used for prophylaxis in immune-compromised individuals. No information is available on their clinical use during breastfeeding. Because tixagevimab and cilgavimab are large protein molecules, the amount in milk is likely to be very low. They are also likely to be partially destroyed in the infant's gastrointestinal tract and absorption by the infant is probably minimal. Until more data become available, tixagevimab and cilgavimab should be used with caution during breastfeeding, especially while nursing a newborn or preterm infant.