Heavy oil demands more energy for its lifting to the surface facilities. A critical parameter that can be altered to enhance the production from the reservoir is the viscosity. Lowering oil viscosity predominantly achieved by thermal methods. This study investigated thermal encroachment in the sand pack layers as simulated heavy oil reservoir was generated by the microwave stack heated mixtures of 22 0API of Indonesian heavy crude, nano-ferrofluidFe2O3 and saturated brines. The wave guide was used to focus microwave radiation into the sand bed. The experimental results showed thatmicrowaveheatingwith maximum output power of 900 Watt and Fe2O3 as the nano particles, works at the frequency of 2.45 GHz reduces oil viscosity from 4,412.11 cP on its pour point at 51 0C to 134.24 cP at 90 0C. Thermal heating with nano ferro fluidsdecreased the viscosityof heavyoiland make it easierto beflowed. Theincreasesoftemperature are directly proportionalwithpoweroutput and nano-ferroconcentration.