Biological synthesis of silver nanoparticles using Glycine max (soybean) leaf extract as reducing agent was reported. The effect of different soybean varieties on the synthesis of silver nanoparticles was investigated. The microstructure of silver nanoparticles was identified from transmission electron microscopy (TEM) and the particle size of silver nanoparticles synthesized by this processes were from 25 to 100 nm. X-ray diffraction (XRD) analysis showed that the synthesized silver nanoparticles crystallized in face centered cubic (FCC) symmetry. The purity and the agglomerations of silver nanoparticles were respectively investigated through particle size and FTIR analysis. Soybean leaf extract shows rapid reduction of silver ions and yields organic free silver nanoparticles.