Studies were carried out on a novel bioreactor designed for the production of animal cells. The aim is, to provide 3D cell proliferation under the influence of low gravity together with gentle mixing and low shear stress. HepG2 cells were used in the experiments to show that this bioreactor can provide low shear forces and a micro-gravity effect considering the results from its Computational Flow Dynamics (CFD) analyses. This bioreactor design has a horizontally positioned cylindrical body and two U-shaped agitators placed opposite to each other. This opposing blade formation, has a reducing effect on each other's hydrodynamic forces and forms a region with low shear stress character in the center of the bioreactor. First of all, the hydrodynamic forces formed inside this bioreactor, which was designed on the basis of CFD simulations, were examined. Afterwards, this novel designed low shear horizontal bioreactor (LSB-R) was manufactured according to the CFD analysis, and simulations. Then, production trials were conducted to determine the success of LSB-R in spheroid production. Thus, by evaluating results obtained from the production trials in accordance with cell culture, it has been shown that LSB-R, which design and patenting phase has been completed, can provide low shear stress.