Due to the ever increase in energy demand, it becomes imperative to design appropriate reactor for the conversion of available raw materials to energy source such as bio oil. A fluidized bed reactor is one the most promising reactor for the conversion of biomass to bio-oil via pyrolysis. This work take into consideration the design of fluidized bed reactor and its subsidiaries (cyclone, filter, condenser and feed hopper) to be used for bio-oil production using sawdust as the feedstock. The operating conditions were temperature between 400-6000C, pressure 9.9atm and flow rate 1.86m/s. From the design calculations, it was found that the volume of the reactor, area, height, diameter and minimum fluidized velocity were 15.0796mm3, 5026mm2, 300mm, 80mm and 1.86m/s respectively. The material for construction for the reactor is stainless steel because of its high thermal conductivity and resistance to corrosion.