The subcellular distribution pattern of kallikrein was compared with that of amylase and acetylcholine in submaxillary gland homogenates of the guinea-pig.2. Kallikrein was located in particles which sedimented in the nuclear (46%) and mitochondrial (17%) fractions. These particles were probably similar if not identical to zymogen granules.3. The above observations would support a digestive role for salivary kallikrein.