The morphogenesis and cytogenesis of the salt gland was studied in various embryonic stages of the viviparous Oman shark, Iago omanensis, from the Gulf of Aqaba, Red Sea. The primordium of the gland is revealed in embryos of 18 mm total length (TL) as a protrusion of the gut posterior to the spiral valve, enveloped in the peritoneal epithelium. In 30 mm TL embryos the glandular parenchyma begins to be organized into secretory tubules extending radially and opening into the central canal of the gland. From this stage on the developments include: thickening of the gland capsule and formation of internal lobules by extensions of connective tissue; strong amplification of the basolateral cell membranes of secretory cells into the cell-cytosols; enlargement of the gland by hypertrophy and hyperplasia of the ion-transporting cells. In 65 (±5) mm TL embryos the gland closely resembles that in adult fish and in pre-term juveniles of 165 (±5) mm TL the gland in general morphology and cytology is identical to that of adults. The results demonstrate that at time of liberation into the environment the juvenile of Iago omanensis is provided for osmoregulation with a functional gland.