Biotic factors mediated biosynthesis of nanoparticles is considered as an eco friendly and green technological approach compared to chemical and physical methods. This work reports the biosynthesis of silver nanoparticles using the extract of marine sponge, Acanthella elongata. Water-soluble organics present in marine sponge extract were mainly responsible for the reduction of silver ions. UV visible spectrum of the aqueous medium containing silver nanoparticles showed plasmon resonance peak at around 426 nm. The X-ray diffraction pattern (XRD) of 2 theta=38.1°, 44.3°, 64.5° and 77.4°, confirmed the crystalline nature of the silver nanoparticles. Transmission electron microscopy (TEM) analysis of silver nanoparticles indicated the sizes, ranging from 15 nm to 34 nm in diameter and a spherical shaped polydispersal of the particles. Through Fourier transform infrared spectroscopy (FT-IR) analysis the possible biochemical agent present in the marine sponge extract was identified as amines which were the cause for the bioreduction of silver salt to silver nanoparticles.