Barium carbonate (BaCO3) has been widely used in soft and heavy industries such as ferrite magnets, solid oxide fuel cells, optical glass manufacturing, coatings, and polymeric composite materials as well as ceramic and brick industries. Using BaCO3 in nano sizes will improve some of the physical properties of materials such as tensile strength, opacity, and thermal resistance. Production of BaCO3 by chemical method requires extensive crystallization times and higher temperatures. Production of BaCO3 by carbonation method usually yields particles with some agglomeration. In a study, conducted by our group funded by The Scientific and Technological Research Council (TUBITAK), a method was developed to synthesize hollow nano Calcium Carbonate (CaCO3) particles. It was aimed to apply the developed method, which is unique in its kind, to produce nano BaCO3 particles in different morphologies. Parameters such as effect of barium hydroxide (Ba(OH)2) concentration, CO2 flow rate, length in reaction chamber, and stirring rate were studied. Conductivity and pH values of the solution were monitored during crystallization. Surface morphology and crystal structure of the produced BaCO3 particles were characterized by Scanning Electron Microscopy (SEM) and X-Ray Diffraction (XRD), respectively. It was shown that rod-like BaCO3 particles produced in nano sizes with almost homogeneous size distributions. The rod-like BaCO3 particles had a diameter from 100 to 400 nm and an aspect ratio of about from 3 to 10. The produced rod-like nano BaCO3 were all in orthorhombic phase of BaCO3 called as Witherite.