Hexamine is used as corrosion inhibitor for Carbon steel in different concentrations of Hydrochloric Acid medium at three different temperatures 25, 30, 350C. Corrosion rate and Percentage Corrosion Inhibition Efficiency (PCIE) in presence and absence of inhibitor was calculated by weight loss method, electrochemical polarization experiments and Impedance spectroscopy techniques. Surface study of corroded and blank specimens was carried out by SEM and Metallurgical research Microscopy techniques. Different concentrations of (100, 200, 400, 600, 800 and 1000 ppm) was tested in different concentration of HCl solution i.e. 2.0, 1.0 and 0.1 N. Observed results show that percentage corrosion inhibition efficiency increases with increase in concentration of corrosion inhibitor. Effect of temperature on percentage corrosion inhibition efficiency was also studied. As the temperature increases percentage corrosion inhibition efficiency decreases. It is also observed that percentage corrosion inhibition efficiency decreases with dilution of HCl. Hexamine acts as a very good inhibitor for Carbon Steel in different hydrochloric acid medium.