Statistics for The inhibiting effect of N - cyclohexyl - N?- phcnyl thiourea (CPTU) and N-naphthyl-N?- phenyl thiourea (NPTU) on the corrosion of mild steel in aqueous solution of 0.1 N H<inf>2</inf>SO<inf>4</inf> have been demonstrated using potentiodynamic polarization technique. The polarization data have shown that these compounds act as efficient anodic inhibitors for mild steel. Adsorption of these compounds on the mild steel surface was found to obey Temkin's adsorption isotherm. Good inhibition efficiency (IE) was evidenced in both the compounds and it was found to vary with concentration of the inhibitors. The kinetic parameters of adsorption obtained reveal spontaneous adsorption and a strong interaction of the compounds on the mild steel surface. © 2006 SAEST.