Carcinoembryonic antigen (CEA) was detected in perchloric extracts of 14 specimens of human saliva. Its presence was independent of the ABO blood group and secretor status. CEA was characterized in pooled perchloric extracts of saliva by exclusion volume on gel filtration, electrophoretic motility, and immunologic reactivity on immunodiffusion and radioimmunoassay. The presence of even minute amounts of CEA in normal saliva was another proof of the lack of cancer specificity of this glycoprotein.