Two of the birds were reportedly found dead, as well as two foxes.
"[The poisoning] seems to have been caused by the ingestion of an ill animal or one that ate another being with some phosphorate compound," the regional director of the Chilean Farming and Cattle Service, Pablo Vergara, told the Argentine newspaper Clarin.
The chemical compound can be found in herbicides and poison used to kill animals considered to be pests.
The poisoned condors were taken to a veterinary clinic, given an antidote and are said to be recovering.
The possibility of finding more animals with the same symptoms has not been ruled out.
The Andean condor is one of the world's biggest bird species and is considered a symbol of the region.
Scientists estimate less than 10,000 condors live in the wild.