The accumulation and distribution of lead granules in the major organs of Macrobrachium nipponense were studied by means of histochemistry, transmission electron microscope (TEM) and atomic absorption spectrophotometer (AAS) analysis. The results showed that many high electronic dense lead granules (EDG) were found primarily in the antennal gland of this species exposed to 0.625 mg.L-1 Pb2+ for 10 days. Under TEM, lead granules were deposited in lysosome, then gradually accumulated in cell apex, and finally individually discharged into gland lumen by apocrine secretion and excreted with urine. There was a small quantity of lead granules in the cells of midgut. Many vacuolus were observed in the cytoplasm of the cells, and the nuclear membranes and cristae in mitochondria were disintegrated partially. The structure of hepatopancreas cells basically remained intact, although there were a few of lead granules in the cells. No lead granule was found in the cells of gills, but a few of lead granules adsorbed on the surface of gill filaments among the gill filaments. The highest concentration (637.6 mg.kg-1) of lead was found in antennal gland by AAS, suggesting that the antennal gland might play an important role in detoxifying process of lead.