Kaempferol (3,5,7,4'tetrahydroxyflavone), a flavonol present in a variety of plant sources, has been used for the formation of gold nanoparticles (k-AuNPs) and these particles have been evaluated for their anti-cancer properties. These nanoparticles have been formed at room temperature (RT) without any other stabilizing agents and are studied for the first time. The size of k-AuNPs is observed to be 16.5 +/- 2.5 nm through high-resolution transmission electron microscopy (HR-TEM). The k-AuNPs are found to be hemocompatible and have anti-oxidant properties which have been evaluated using hemolysis assay and DPPH radical scavenging assay respectively. In the presence of k-AuNPs, there is a dose and time dependent decrease in viability of MCF-7 breast cancer cells which has been confirmed using ethidium bromide-acridine orange (EtBr-AO) staining, phase contrast microscopy (PCM) observations, and scanning electron microscopy (SEM). The anti-proliferation activity of k-AuNPs was assessed using CyQuant assay. The k-AuNPs induce apoptosis of the MCF-7 cells as evidenced through increase in the sub-G1 (hypodiploid) population. They also inhibit the vascular endothelial growth factor (VEGF) induced angiogenesis as demonstrated through chorioallantoic membrane assay (CAM). These results suggest the potential of k-AuNPs as a promising anti-cancer agent in breast cancer therapy. (C) 2015 Elsevier Ltd. All rights reserved.