Antennal glands of crustacean are excretory organs that excrete organic wastes and the fluids of the body. Na+-K+ ATPase (sodium-potassium
adenosinetriphosphatase) is the main enzyme for regulation of ions and water (osmoregulation). In this study, the general organization, ultra structure of the cells and the localization of Na+-K+ ATPase were examined in the antennal glands of A, leptodactylus. For the general organization study, the glands were fixed and dehydrated in ethanol and the blocks were made in paraffin then sections were cut for light microscopy observations. For ultrastructuralstudy of the cells, samples were fixed in glutaraldehyde and observed under electron microscopy, Na+-K+ ATPase localization were performed through immunoflourescence light microscopy by using antibody IgGa5. Each gland is composed of four units, including the coelomosac, the labyrinth, the tubule and a voluminous bladder, linked by a short duct to the urinary pore. Ultra
structural observations have shown that the cells of coelomosac possess pdocytic feature. These cells have Golgy complex system, vacuoles, endocytotic vesicles and they posses distinctive pedicels. The labyrinth cells present basal membrane inflowing, apical vesicles, apical microvillus and apical extrusion cytoplasmic. The tubule is consist of two sub-unit (tubule proximal and distal) and the cells present in common basal membrane enfolding associated with mitochondria, and cytoplasm including numerous vacuoles and mitochondria. These cells have not apical microvillus and they also present distinctive characters in each sub-nit Na+-K+ ATPase was detected through immunofluorescene in the tubule and bladder cells with an increasing concentration. A weak fluorescence was also shown in labyrinth and no immunofluorescence was detected in the coelomosac. The cells of the tubules and the bladder present morphological and enzymatic feature of ionocytes. Thus, the antennal glands of the A. leptodactylus possess active ion exchange capabilities and participates in osmoregulation.