In this study, a successful synthesis of gold nanoparticles (AuNPs) using extract from the Carambola fruit was carried out. Remarkably fast reduction of Au3+ ions was observed when aqueous chloroauric acid was treated with star fruit powder at 60 ºC and this was obtained without the use of any stabilizing or reducing agents. The UV-visible, FT-IR, DLS, XRD, SEM and TEM were used to study the synthesized AuNPs. The FT-IR studies suggested that the phenolic group may have contributed to the reduction of Au3+. The DLS particle size analysis and TEM measurements revealed that AuNPs had a mean particle size of 10 nm and were nearly spherical in form. The crystalline character of AuNPs was established by TEM-SAED image and XRD analyses. Zeta potential measurements were used to analyze the stability of AuNPs. The synthesized AuNPs effectively scavenge free radicals such as DPPH, NO• and H2O2 with % inhibition values of 57.12, 58.75 and 60.23, respectively. The MTT assay of the anticancer activity demonstrated that the synthesized AuNPs worked effectively against MCF7 cell lines and are comparable to those of standard cancer drugs.