The study attempts to evaluate the heavy metal (mercury) pollution status in water, sediment, macrophyte, plankton, macroinvertebrates and fish (herbivorous and carnivorous) of Gandhisagar reservoir, Mandsaur district, Madhya Pradesh. The samples were acid digested and subjected to AAS analysis for Hg. The results showed that the metal in water, sediment, macrophyte, plankton, macroinvertebrates (benthos) and fish are distinguishable with sediment and biota samples are more susceptible to metal accumulation. The Hg levels detected reveals that in the present study Hg accumulation is higher in all the food fishes than that of water and sediment which is suggesting biological transfer of heavy metals through food chain.