Preparing high coercivity CoFe2O4 nanoparticles suitable for high-density recording is still a challenge. The theoretical values for a random system of spherical, non-interacting single-domain CoFe2O4 particles with cubic anisotropy have been predicted to be: Ms (300 K)=80.8 emu/gm, Hc(300 K)=5.3 kOe and Mr/Ms=0.83. Here, for the first time, we report the synthesis of CoFe2O4 nanoparticles of about 40 nm with unusual high coercivity of 4.3 kOe at room temperature (RT).