The inhibiting effect of Chenopodium extract against the copper corrosion in 1M HNO3 was studied by weight loss, potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) and electrochemical frequency modulation (EFM) techniques. Surface morphology was tested using scanning electron microscope (SEM).The results showed that the inhibition efficiency increases with increasing the inhibitor concentration, while it decreases with increasing the temperature. The adsorption of Chenopodium extract on the copper surface obeys Temkin adsorption isotherm. Some thermodynamic parameters were calculated and discussed. Polarization curves showed that Chenopodium extract is mixed-type inhibitor but the cathode is more polarized than the anode. The results obtained from chemical and electrochemical techniques are in good agreement.