Nanotechnology is the term used to describe the creation and exploitation of materials with structural features in between those of atoms and bulk materials,34 with at least one dimension in the nanometer range. Metal nanoparticles have various functions that are not observed in bulk phase and have been studied extensively because of their exclusive catalytic, optical, electronic, magnetic and antimicrobial wound healing and anti-inflammatory properties. The microbial synthesis of nanoparticles had been recently recognized as a promising source of nanomaterials. Due to the mass production of NPs as the easiness of controlling yeasts in laboratory circumstances, the synthesis of numerous enzymes and rapid growth with the use of simple nutrients, the yeast strains possess more benefits other organisms. Selenite is the most toxic form of Se; hence, biogeochemical cycles involving reduction of selenite (Se+4) to elemental selenium (Se0) are of paramount importance. Selenium nanoparticles (SeNPs) are gaining importance in electronics and optics due to their enhanced semiconducting, photoconducting, photoelectrical, and catalytic properties. In this paper, the production of this nanoparticle was made by the most efficient marine yeast strain MY05. SeNPs display an optical absorption bond at 323 nm and the presence of elemental selenium was confirmed by Energy dispersive x ray (EDX) analysis. This strain synthesized nanoparticles under a variety of conditions. Scanning electron microscopy (SEM) and Transmission electron microscopy (TEM) micrographs showed both extra and intra cellular synthesis of Selenium nanoparticles.