In this paper, we have investigated the influence of thermophoresis and Brownian motion on three dimensional slip flow of a conducting Casson nanofluid and heat and mass transfer over an exponentially stretching sheet. The effects of relevant parameters on velocity, temperature and concentration are illustrated through graphs and tables. The growth in Brownian motion and thermophoresis parameters enhances the thermal boundary layer and temperature field. Further, the Nusselt number for different values of Pr and temperature exponent A is calculated for the base fluid and the results are validated with the earlier results. Also, noticed that the present results have good agreement with the previous results. © 2019 by American Scientific Publishers.