In this study, soluble oil-based titanium dioxide was employed as a drilling fluid to enhance the performance of drilling process in terms of smoothness. The results of drilling process in the presence of titanium dioxide as an additive were compared with the dry condition and once applying pure drilling fluid. Further, forced convective heat transfer coefficient of the soluble oil-based titanium dioxide nanofluid flowing through a horizontal circular tube was also investigated experimentally under constant wall heat flux boundary condition. To this end, soluble oil-based titanium dioxide nanofluids were prepared at the weight concentrations of 03, 0.6 and 1%. To have a proper colloidal stability, gum Arabic (GA) was used as a surfactant with 1:1 weight ratio of GA and titanium dioxide. The results showed that the addition of titanium dioxide nanoparticles to the soluble oil decreased significantly the surface toughness of work-piece as well as the drilling temperature as compared to the pure soluble oil and dry condition. Moreover, as the concentration of titanium dioxide increased, the convective heat transfer coefficient increased significantly, and it was further improved by increasing Reynolds number. Note that increasing the concentration of nanoparticle into the base fluid was more effective than that of improving Reynolds number in the range studied herein. (C) 2016 Elsevier B.V. All rights reserved.