The present study was conducted to study phytochemical composition, antioxidative and antiproliferative effect of methanol extract of Butea monosperma leaf. Superoxide scavenging assay, metal chelating assay, DPPH and MTT assay were employed. MTT assay was performed on A-549 human lung carcinoma cells and chick embryo fibroblasts were used as the control. Deoxyribonucleic acid fragmentation and real time assay was performed to check apoptosis and gene expression level. Results obtained indicated that the methanol extract of Butea monosperma exhibited high level of antioxidant activity compared to standard antioxidant. Methanol extract and different fraction of the extract exhibited significant antiproliferative activity against lung cancer cell line. The chloroform fraction was found to be most active in MTT assay against A-549 cells while it was less toxic to normal cells. Cells exposed to LD50 concentration of the chloroform fraction exhibited breakdown of DNA. Increased expression of p53, Bax and caspase-3 gene and reduced expression of Bcl-2 gene gave evidence that the chloroform fraction of Butea monosperma might induce apoptosis. These results indicated that the methanol extract and its fractions of Butea monosperma leaf possessed immense potential for tumour treatment. Therefore, it would be necessary to carry out further studies to isolate and identify the active principles responsible for these activities.