Mild protein-calorie deprivation in mice decreases their early nonspecific inflammatory response to an injection of BCG or tuberculin into the footpad. After an injection of BCG, the size of the granuloma and the delayed hypersensitivity reaction to tuberculin significantly decreased. This decrease in cell-mediated immunity was paradoxically accompanied by a fall in bacillus multiplication at the popliteal ganglion, i.e. the site of BCG injection. A reduction in microbial multiplication was also observed in the spleen after intraperitoneal injection of Listeria and in the liver after intravenous injection.