Serological survey for detecting subclinical infections with Junín virus, the etiological agent of Argentine hemorrhage fever, was carried out in a group of 107 individuals working in laboratories where this virus was handled. The group was divided into high risk and low risk personnel according to the degree of exposure to the virus. Neutralizing tests were performed in Vero cell cultures to detect circulating antibodies. Results were evaluated comparatively with those obtained in a previous survey. This study shows that among high risk personnel three out of 52 developed neutralizing antibodies (NA) against Junín virus; one of them had a mild clinical illness, and the other two showed no overt disease during this period. No one among the low risk group developed NA against Junín virus.