Malaria is one of the most devastating diseases of tropical countries with clinical manifestations such as anaemia, splenomegaly, thrombocytopenia, hepatomegaly and acute renal failures. In this study, cases of thrombocytopenia and haemoglobinemia were more prominent in subjects infected with Plasmodium falciparum (Welch, 1897) than those with Plasmodium vivax (Grassi et Feletti, 1890). However, anaemia, jaundice, convulsions and acute renal failure were significantly high (3-4 times) in subjects infected with P. falciparum than those infected with P. vivax. The incidence of splenomegaly and neurological sequelae were 2 and 6 times higher in P. falciparum infections compared to the infections of P. vivax. Both in P. vivax and P. falciparum malaria, the cases of splenomegaly, jaundice and neurological sequelae were almost double in children (<10 years) compared to older patients. The liver enzymes were generally in normal range in cases of low and mild infections. However, the AST, ALT, ALP activities and serum bilirubin, creatinine, and the urea content were increased in P. falciparum and P. vivax malaria patients having high parasitaemia, confirming liver dysfunction and renal failures in few cases of severe malaria both in India and Saudi Arabia.