Manganese dioxide (MnO2) decorated graphene oxide was modified on the glassy carbon (GC) surface. The nanofilm covered electrode was used for determination of Pb2+ and Cd2+ via differential pulse anodic stripping voltammetry. Characterization of the modified electrode was performed via cyclic voltammetry, TEM, XPS, and XRD. The limit of detection (S/N = 3) of the method was calculated as 1.24 pM for Pb2+ and 0.14 pM for Cd2+ with the linear calibration curves ranged from 1 x 10(-11) M to 1 x 10(-7) M for Pb2+ and Cd2+. The method shows good reproducibility and stability and was successfully applied to measure trace Pb2+ and Cd2+ in seawater samples from Turkey. The recoveries of the Pb2+ and Cd2+ response of the method were up to 96%. (C) 2015 The Electrochemical Society. All rights reserved.