Family Gammaridae is the most well-known and diversified among Amphipod order. Pontogammarus maeoticus is the most abundant sublittoral amphipod of southern cost of Caspian Sea. In present research work Caspian gammarus has been studied morphologically and new characters have been established using its mouthparts. Specimens were collected through sieve, transferred to laboratory, cleaned and finally fixed in 70% ethanol. Body parts were dissected and studied under stereo microscope, light microscope and by SEM. Micro photographs and diagrams drawn showed general details of brackish water gammarus to be present and mouthparts of basic type. Mouthparts were composed of Mandible, Maxillae 1, Maxillae 2 and Maxilliped.