The intracellular localization of beta-NADPase in rat hepatocytes and Kupffer cells has been studied and compared with the pattern of TPPase in these cells. The reaction product for beta-NADPase is present in some but not all hepatocytes in two cisternae on the trans aspect of the Golgi apparatus. It is absent from the trans-most lamella and the GERL of hepatocytes. TPPase, on the other hand, is limited to the first Golgi cisterna on the trans aspect with sprinkles of reaction product in the second lamella. Considering that TPPase is a marker of the trans Golgi lamella and hepatocyte Golgi stacks contain usually 2-4 lamellae, our observations suggest that beta-NADPase is localized in the trans as well as in the intermediate Golgi lamellae of liver parenchymal cells. In Kupffer cells, the reaction product for both beta-NADPase and TPPase was found in some but not in all cells. The enzyme beta-NADPase was localized in the rigid lamella and the tubulovacuolar system of GERL. This pattern differed significantly from that for TPPase, which was found in 2-3 cisternae at the trans aspect of the Golgi complex in Kupffer cells. These observations demonstrate the difference in the localization of beta-NADPase in hepatocytes and Kupffer cells. Such differences should be taken into consideration in studies of Golgi fractions, when phosphatase reactions are used as specific markers of Golgi components.