Corrosion is a major issue affecting the durability and performance of various metallic materials, leading to substantial economic losses and safety hazards. The corrosion of reinforced steel in sodium chloride environment poses a significant concern for various industrial applications. This study aims to investigate the corrosion inhibition properties of expired pentoxifylline drug on reinforced steel in a 3.5% NaCl solution. The mass loss method was utilized to quantify the corrosion rate and assess the efficiency of the expired pentoxifylline drug as a potential corrosion inhibitor. The results indicate that the corrosion rate of steel in the 3.5% NaCl solution decreased significantly in the presence of expired drug. Higher concentrations of expired drugs have shown a greater impact on corrosion inhibition. Investigation of the effects of temperature on corrosion inhibition efficacy. The inhibition efficiency increased with increasing concentrations of the inhibitor and decreased with increasing immersion time. The experimental data were tested according to the Langmuir adsorption isotherm, through which the equilibrium adsorption constant (Kads) was calculated and found to be 4.38 litres mol-1 as the maximum value when immersed for one day. The standard free energy of adsorption (∆G_ads^o) ranged from 45 to 30.5 kJ mol-1................. Keywords:..... Reinforced steel, sodium chloride medium, inhibition, expired drugs, pentoxifylline