The inhibitive effect of theophylline anhydrous on aluminum corrosion in hydrochloric acid solution was investigated using chemical and electrochemical techniques. It was found that the compound acts as good corrosion inhibitor with inhibition efficiency more than 99.9%. The inhibition efficiency was found to increase with inhibitor concentration and exposure time. On the other hand it decreases by rising the temperature. The inhibition action was discussed in view of adsorption of the organic compound molecules on the aluminum surface. It was found that the adsorption of theophylline anhydrous on aluminum surface follows Langmuir adsorption isotherm. The thermodynamic parameters for the corrosion process in free and inhibited media were calculated and interpreted.Corrosion of metals and alloys is a disaster which causes a large economic loss in different human activitiesThe corrosion process is thermodynamically spontaneous and cannot be totally stopped anyhow. However, there are continuous trials to develop methods for decreasing the corrosion to its minimum rate