The ability to quickly detect potential threat is an important survival mechanism for humans and other animals. Past research has established that adults have an attentional bias for the detection of threat-relevant stimuli, including snakes and spiders as well as angry human faces. Recent studies have documented that preschool children also detect the presence of threatening stimuli more quickly than various non-threatening stimuli. Here we report the first evidence that this attentional bias is present even in infancy. In two experiments, 8- to 14-month-old infants responded more rapidly to snakes than to flowers and more rapidly to angry than to happy faces. These data provide the first evidence of enhanced visual detection of threat-relevant stimuli in infants and hence offer especially strong support for the existence of a general bias for the detection of threat in humans.