Essential oil of aerial parts of Thymus algeriensis was obtained by hydrodistillation and analyzed by G C and GC/MS. 44 components were identified accounting 90. 2% of the total oil, which borneol (28%), camphene (20.9%) and camphre (15.7%) were the major compounds. Inhib ition effect of this essential oil (EOTA) on mild m ild steel in 1.0 M HCl solution was studied. Inhibition efficien cy of plant extracts were carried out by using chem ical (weight loss method) and electrochemical techniques (potent iodynamic polarization and electrochemical impedanc e spectroscopy). The effect of temperature on the cor rosion behavior of mild steel in 1.0 M HCl with add ition of plant extracts was studied in the temperature range of 30 8 - 343 K. The adsorption and kinetic parameters f or mild steel/EOTA/1.0 M HCl system were calculated from ex perimental gravimetric data and the interpretation of the results are given. The polarization studies showed that J EOTA acts as mixed-type inhibitor. The Nyqui st plots showed that on increasing EOTA concentration, incre ases charge transfer resistance and decreases doubl e layer capacitance. EOTA obeys the Langmuir adsorption iso therm.