The main complication in betulinic acid (BA) based drug delivery has been observed due to its bulk structure. The present study demonstrates the potential effects of self assembled nano size betulinic acid (SA-BA) by treating human leukemic cell lines (KG-1A and K562) and its normal counterpart. Self assembly property of BA was investigated using SEM and DLS study which showed that the BA forms fibrous structure having few nanometers in diameter. Selective anti-leukemic efficacy study of SA-BA was investigated by cell viability assay. Mode of leukemic cell death and probable pathway of apoptosis was monitored by measuring ROS level, pro and anti-inflammatory cytokine status and expression of caspase-8 and caspage-3 by immunocytochemistry. Higher efficacy of SA-BA over non-assemble BA was monitored toward cancer cells, with no relevant toxicity to normal blood cells. SA-BA facilitated reactive oxygen species (ROS) mediated leukemic cell death, confirmed by pre-treatment of N-acetyl-L-cysteine. Induction of apoptosis by SA-BA treatment increased pro-inflammatory cytokines, specifically potentiated TNF-α mediated cell death, confirmed by expression of caspase-8 and caspage-3 by immunocytochemistry. This study explored the better anti-leukemic efficacy of SA-BA over BA and this modification will enrich the use of BA in cancer therapy.