The steady movement salts swept from the earth’s crust by multiplicity of sources drained towards sea. Finally the evaporation of seawater to the atmosphere makes the ocean salty. Gaseous and solid discharges from volcanic activity, suspended solids run-off, and dissolving of materials from deposition of sediments on the oceanic floor also contribute the high salt concentration in the seawater. The quantity of total dissolved salts is reduced as a result of precipitation, surface water run-off or melting of ice caps over the sea. This study was conducted to investigate the amount of dissolved salt present in seawater in the vicinity of Karachi. For this purpose six locations were selected around the city; such as, Lyari River, Sand Pits, Karachi Port Trust, Kiyamari, Manhora and PRC Towers. It was found that the amount of total dissolved salt in seawater was more or less similar at five locations except one place at the joining point of Lyari River. The chlorides, sodium, sulfates, potassium, magnesium and conductivity were found 22, 18, 13, 06, 09 and 13 times lower at Lyari among other places. It is concluded that fresh water from Lyari drain reduced the dissolved salt content near the joining point of fresh water with seawater.