About 110 patients were enrolled to study the atypical presentations and the chloroquine sensitivity pattern of Plasmodium vivax malaria. The diagnosis was made from Giemsa stained peripheral blood smear. The co-infection of falciparum malaria was excluded both by smear and ParaSight F-test. After a thorough clinical work up, biochemical investigations were done. The fever clearance and parasite clearance time were determined in all cases. Absence of malarial paroxysm (22.8 per cent), migrainous headache (4.5 per cent), myalgia (6.3 per cent), episodic urticarial rash (1.8 per cent), relative bradycardia (13.6 per cent) and postural hypotension (2.7 per cent) were the atypical manifestations encountered. Besides this, severe forms like jaundice (7.2 per cent), cerebral involvement (0.9 per cent), severe anaemia (7.2 per cent), thrombocytopenia (3.6 per cent) and pancytopenia (0.9 per cent) had been detected. All, except the patient with cerebral involvement were treated with chloroquine patients responded well to the treatment except two (1.8 per cent) patients who had chloroquine resistance. This study showed that vivax malaria can present with atypical and protean manifestations. The changing clinical profile along with development of chloroquine resistance may be considered as a warning signal.