The activity of LDH, MDH, G1DH, GOT, GPT, and CA was measured in the glomeruli, proximal convolutions, distal convolutions, medullary rays, outer zone of the medulla, inner zone of the medulla, and papilla dissected from 16 µ frozen dried sections of the human kidney. The activity of phosphate activated glutaminase, pyruvate activated glutaminase and non-activated glutaminase was determined in fresh homogenates from cortex, medulla and papilla. The enzyme activity was lower in glomeruli than in most other parts of the nephron. The activity of LDH, G1DH, GOT, and CA was highest in the proximal and/or distal convolutions. The maximum MDH and GPT activity was in the medullary rays. The highest activity of the glutaminases was found in cortex, the lowest in the medulla. The distribution patterns in the nephron of CA, glutaminases, GOT, GPT, and G1DH are compatible with the sites found in experimental animals for the production and excretion of hydrogen ion and ammonia, and suggest a very similar localization and mechanism in the human kidney