Polysaccharide and protein fractions of Klebsiella pneumoniae were labeled with C14 by biosynthesis from labeled sodium acetate or glucose. These and other fractions of the labeled organisms were injected intravenously into young guinea pigs and incorporation into various tissues was followed up to 2 months after the injection. Radioactivity in the plasma disappears within 7 days while the organs having the greatest activity are the adrenal, spleen, liver, lung, and cervical lymph nodes. Although the greatest quantity is incorporated in the liver, the adrenal has by far the highest concentration per g of tissue. Autoradiographs show activity of the polysaccharide fraction in the zona fasciculata of the cortex. This incorporation in the adrenal increases gradually after injection, reaching a maximum in about 7 days after which it remains in considerable concentration by the end of 2 months. The liver, spleen, lung and other organs reach maximum activity within the first hour, decline thereafter and are without detectable activity at the end of 2 months.