This study endeavours to evaluate the measurement of lipid peroxidation in patient with cerebral thrombosis and haemorrhage and also to correlate its level with the lesion size in these patients. Seventy five subjects were included in the study comprising 25 each of cerebral thrombosis and haemorrhage while 25 comparable subjects scored as control. Serum malondialdehyde (SMDA) as a measure of lipid peroxidation was estimated on first day of admission. The study emphasizes that SMDA levels were raised significantly (p < 0.001) in the study groups compared to control and varies according to size of lesion with significant correlation (P < 0.01). However, no correlation was found between large and small lesion of thrombotic and haemorrhagic study group, when compared between themselves. Therefore, it is concluded that SMDA is involved in the pathophysiology of these lesions and has definete corelation with the lesion size.