In this work, silver nanostars were synthesized using silver nitrate, ascorbic acid and PVP, in a molar ratio of 3.6:71.5:X, respectively. Where x is the concentration of PVP which varied from 0.1 to 10 mM. The behavior of morphology and size of the nanostars was studied by scanning electron microscopy and UV-Vis absorption. In addition, SERS substrates were fabricated depositing silver nanostars over copper film in order to determine which morphology and size offer the lowest detection limit of methylene blue and crystal violet. These studies allow us to identify nanostars as an excellent nanostructure for the fabrication of ultrasensitive SERS substrates for the detection of persistent organic pollutants.