For the first time, microalga Dunaliella salina was successfully applied for synthesis of silver nanoparticles. The process of nanoparticles production was monitored using UV–Vis spectroscopy which exhibited surface plasmon resonance band at 432 nm. Scanning electron microscopy confirmed the presence of spherical silver nanoparticles having diameter in the range of 15–40 nm. Crystalline nature of produced nanoparticles was confirmed by X-ray diffraction, and Fourier transform infrared spectroscopy revealed the involvement of functional groups in nanoparticles formation. The changes in the biomass biochemical composition during silver nanoparticles biosynthesis were assessed as well. Formation of silver nanoparticles was accompanied by the decrease in proteins, β-carotene and lipids content in biomass.