This chapter describes the occurrence of saltwater/freshwater interface in coastal aquifers. It has a brief description of the physics, hydraulics, and mathematics behind the theory of saltwater intrusion and the saltwater/freshwater interface. It also includes a section on numerical modeling techniques and the available computer models for saltwater-intrusion problems in coastal aquifers. Anthropogenic effects on saltwater intrusion such as changes in land use and landscape vegetation cover, groundwater pumping patterns, and the amount of pumping are also discussed. Finally, remedies, control and management of saltwater intrusion such as implementation of recharge wells, creation of artificial recharge basins, and construction of barriers are discussed. This chapter is expected to be useful to agricultural communities of coastal plains whose irrigation water is solely dependent on groundwater resources. It may also be of interest to individuals working in coastal-watershed and land-management businesses and governmental or local decision makers by addressing the problem of saltwater intrusion into coastal aquifers and its possible remediation and control techniques.