In the present investigation, the effect of different concentrations of NaCl on growth and development, organic constituent of Ceriops roxburghiana, a dicotyledonous halophyte has been studied. Ceriops roxburghiana survived a wide range of NaCl salinity ranging from 100 to 700 mM. The upper limit for the survival of this species to NaCl salinity was 700 mM. Results of the present study indicated that the optimal salt concentration for the overall better performance of the seedlings of Ceriops roxburghiana was 300 mM NaCl. Since the growth and development of this species were improved in the presence of NaCl and it could tolerate high concentration of Cl- in the cell sap, it could be designated as “facultative halophyte”. The growth parameters such as shoot and root length, fresh and dry weight increased with increasing salinity upto 300 mM NaCl.