Hyperreactive malarial splenomegaly, one of the major causes of splenomegaly in tropics, has been often reported in expatriates of non-tropical settings. Essential features are recurrent malarial infection, overproduction of IgM and hyperplasia of lymphoreticular system. The practice of diagnosing the condition by exclusion of obvious causes of splenomegaly in the tropics has been abandoned. There are specific criteria for the diagnosis. Huge splenomegaly >10 cm below costal margin, serum IgM more than 2 x standard deviation (2SD) above the local mean, high titre of malarial antibodies and response to antimalarial drugs are the cornerstones of the diagnosis. Splenic lymphoma with villous lymphocytes coexists with this condition and it should always be considered in the differential diagnosis of unresponsive or poorly responsive cases of hyperreactive malarial splenomegaly. Condition with fever and acute haemolysis in HMS has been termed as Fulminant tropical splenomegaly syndrome. Treatment of the condition depends on antimalarial (chloroquine/ proguanil/ pyrimethamine) chemoprophylaxis for 1 year or more.