Magnetic susceptibility has been determined for sediments from the riverine, estuarine, and marine environments near Mulki, west coast of India, to understand the behavior of magnetic minerals as they enter the oceanic realm through the estuary. In the riverine environment, magnetic minerals are bimodally distributed. Magnetic susceptibility is positively correlated with the magnetite weight percentage. The magnetic mineral content decreases from the river head to the river mouth. Well-sorted sediments are rich in magnetic minerals. It is seen that the susceptibility of samples is governed both by the type of minerals present and by their relative abundances. Several instances of the environmental regime/process influencing the magnetic susceptibility and hence the magnetic mineral content are discussed: deposition of magnetic minerals in meander loops, anoxic conditions in the inner shelf, etc. ¿ American Geophysical Union 1994