An outbreak of cholera occurred among passengers who flew on an international flight between South America and Los Angeles, California. Cold seafood salad was statistically associated with risk of illness. Of the 100 passengers with laboratory evidence of infection with V. cholerae 01, 52 had only positive vibriocidal titres, 22 had only isolates confirmed as toxigenic V. cholerae 01, and 26 had both elevated titres and confirmed isolates. Of the 48 isolates, 34 (71 %) were serotype Ogawa and 14 (29%) were serotype Inaba. All isolates were biotype El Tor. The seafood salad, prepared by a caterer in Lima, included shrimp, fish, pineapple, eggs and apples. An investigation by Peruvian health authorities into food preparation practices at the caterer's kitchen did not reveal a mechanism of contamination.