A long term (1990-2000) soil and water salinity monitoring programme was undertaken to address the salinization problem in paddy cum brackish water shrimp cultivation area . The information generated during this period has been presented in this paper. In monsoon season, particularly from August to October soil salinity had increased from 1.4 dS/m to 10.3 dS/m. In between November and February depth of ground water table remained within 0.12 m to 0.33 m and rest of the year it remained at or close to the surface. So, due to presence of ground water table at shallow depth and slower permeability downward movement of soluble salts from the top is very limited. Under Pashur river system average submerged water salinity was found to be 13.8 dS/m to 17.5 dS/m in between March and- May. In Shibsha river system it was found to be 13.2 dS/m to 24.2 dS/m in between February and June. More soluble salts have been accumulated in the topsoil over long period brackish water shrimp cultivation. Increasing tendency of soil pH from 7.5 to 8.2 may be due to high amount of cations like Ca, Mg, and K. High amount of S may be one of the possible reasons for P deficiency in brackish water submerged condition. Soils are rich in B. Cu, Fe except Zn. Late transplantation, without or very little fertilization, without insecticides, use of aged seedlings, wider spacing, relatively high flooding at the time of aman transplantation, minimum tillage and little opportunity of flushing and leaching of fresh water are the common constraints of paddy cultivation in paddy cum brackish water shrimp cultivation area.