Flat plate collectors are widely used collectors in many domestic and industrial applications to harvest freely available and environmentally safe source of energy, i.e. solar energy. Many researches are carried out to make the system cost effective by reducing the installation cost, increasing the efficiency, etc. The application nanotechnology in the form of various nanofluids as working medium in solar flat plat collectors is a relatively recent trend. Nanofluid exhibits enhanced thermal properties as it is the two phase mixture of solid nanoparticles having less than 100 nm diameter and base fluid, which in turn enhances the thermal performance of the system of application. Few investigations have been reported to evaluate the performance of solar flat plate collector using SiO2 nanofluid. In the present paper, thermal performance of solar flat plate collector using SiO2 nanofluid has been experimentally evaluated in terms of efficiency of solar flat plate collector at different volume fractions (0.01% to 0.1%) of SiO2 nanofluid. It has been experimentally confirmed that outlet temperature and efficiency of solar flat plate increases when SiO2 nanofluid is used as compared to water upto 0.08% volume fraction and then it decreases. The maximum value of outlet temperature and efficiency of solar flat plate collector obtained for the case of 0.08% volume fraction of SiO2 nanofluid are 55.78oC and 52.02%, respectively which are 55.78% and 80.40% higher than water as working fluid.