Graphene-sodium polyacrylate-Pd (GN-PAAS-Pd) nanocomposite was synthesized and applied to the amperometric determination of ciprofloxacin (CIP). The electrochemical behaviour of CIP on the nanocomposite was investigated and a chronoamperometry method was developed for the determination of CIP. The results showed that the peak current increased with the CIP concentration in the range 0.18-10.8 mu M with a calibration equation of I-pa (mu A) = 0.867C(CIP) + 0.6521 (mu M) and in the range 10.8-180 mu M with a calibration equation of I-pa (mu A) = 0.1593C(CIP) + 8.2671 (mu M). The detection limit was estimated to be 0.045 mu M (S/N = 3). The modified electrode has been applied to the determination of CIP in samples.