Different techniques have been used to achieve a high heat transfer rate. Among them, one of the advanced techniques is a suspension of nanoparticles in the base fluids as water and coated with aluminum and titanium. The present work has been carried out on a double pipe heat exchanger with twisted tape insert with twist ratio (y/w = 4 and 6) and thickness (0.8mm) for heat transfer investigation of water to water and nanofluid to water with counter flow arrangement under turbulent flow conditions. The computational fluid dynamic code simulates different concentrations of nanofluid (0.01% to 0.19%) in ANSYS FLUENT R 18.1 software. The overall heat transfer coefficients for all concentrations are measured as a function of the hot and cold stream's mass flow rates. The thermal performance parameter overall heat transfer coefficient is compared for nanofluids with water. The work concludes that there is a good enhancement in heat transfer rate using nanofluid.