The term __ampersandsignquot;mangrove__ampersandsignquot; is being applied to the specific ecosystem of the intertidal world in the tropics and subtropics and the plant community of this ecosystem is termed as __ampersandsignquot;mangrove vegetation__ampersandsignquot;. Halophytes as a group have one or more of several physiological adaptations that allow for the survival in the saline environment. A halophyte is a plant which is capable of surviving in a highly salty environment. In the present research an attempt has been made to study the effect of Sodium Chloride on seedling germination constituents of Ceriops roxburghiana. Seedlings were collected from mangrove forest in pichavaram, Tamilnadu, India. Polytene bags sizes with 12__ampersandsigntimes;18 cm were filled with sand, humus and red sand in 1:2:1 ratio. Various concentration of Sodium Chloride solution (0,100,200,300,400,500,600 and 700mM) were prepared by using distilled water. Plantation were separated into 8 groups, each group containing 50 number of plants. Each group of plants treated uniformly by different concentration of Sodium Chloride solution. In addition to this, plants were irrigated with distilled water and maintained as control (0). The effects of Sodium Chloride on seedling germination of the halophyte Ceriops roxburghiana were studied. Germination activity was maintained up to 300 mM NaCl. The NaCl inhibited germination only at concentrations higher than 300 mM.The results indicated that the NaCl salinity stimulated the seedling germination upto the optimal level of salinity (i.e., 100mM and 300mM) and decreased significantly with increased salinity (400 to 700mM). The inhibition of seed germination was proportional to the concentrations of NaCl increased.