This paper describes the synthesis of cobalt ferrite (CoFe 2O 4) nanoparticles and their application in enhanced oil recovery. Cobalt ferrite (CoFe 2O 4) nanoparticles were used as ferrite magnetic feeders with antenna to improve the magnetic field strength and cobalt ferrite nanofluid to improve oil recovery. Cobalt ferrite (CoFe 2O 4) nanoparticles were synthesized by sol-gel method. These nanoparticles were then characterized by using X-ray diffractometer (XRD) and Field Emission Scanning Electron Microscope (FESEM). Cobalt ferrite nanoparticles annealed at 600°C, the particle size is 51.17nm and 26nm as determined by XRD and FESEM, respectively while for the sample annealed at 800°C, the particle size is 62nm as determined by XRD and 60 nm as determined by FESEM. Magnetic measurement results show that initial permeability of cobalt ferrite powder increased and relative loss factor decreased at high frequency. In order to improve the oil recovery, nanoparticles were used in two different experiments. In the first experiment, nanoparticles were used as magnetic feeders with an antenna to improve the magnetic field strength. In the second experiment, nanoparticles were used as nanofluids. Results show that the antenna with magnetic feeders increases the magnetic field strength by 0.94 as compared to antenna without magnetic feeders in the water, and by 5.90 in the air. Magnitude versus offset (MVO) study of antenna with magnetic feeders shows an increase in magnetic field strength of 275 as compared to antenna without magnetic feeders. It is found that antenna with magnetic feeders was able to recover 29.50 and 20.82 of original oil in place (OOIP) in core rock samples A-1 and A-2 respectively. The use of cobalt ferrite nanoparticles as a nanofluid with electromagnetic waves yielded a higher recovery of residual oil in place (ROIP) which is 31.58 as compared to 8.70 when it was used as nanofluid alone. It is investigated that due to absorption of electromagnetic waves by cobalt ferrite nanoparticles the oil viscosity reduces which increase the oil recovery. It can be concluded that the synthesised cobalt ferrite (CoFe 2O 4) nanoparticles can be potentially used for enhanced oil recovery in future. © (2012) Trans Tech Publications, Switzerland.