A numerical study of heat transfer and turbulent fluid flow over a staggered circular tube bank using a computational fluid dynamic code (Fluent 6.2) is presented in this work. The model for staggered arrangements is applicable for use over a wide range of the aspect ratio S-T/S-L when determining heat transfer and turbulent fluid flow over a staggered circular tube bank. The turbulence model used involves the solution of two partial differential equations, one for the kinetic energy of the turbulence and the other for its dissipation rate. The results show that the average heat transfer for tube banks in cross flow depend on aspect ratio (S-T/S-L), Reynolds number, and Prandtl number. The present model gives higher heat transfer rates for all cases of Re number. The higher values of pressure drop distribution usually recorded near the initial of the external tube bank surface in all cases. The maximum velocity in the passage between the upper and lower side was recorded. The present results of the average Nusselt numbers with Re number at aspect ratio (S-T/S-L = 3/2) are in good agreement with the available data of Zukauskas and Ulinskas (1988). Therefore, the present values of the velocity vector at aspect ratio (S-T/S-L = 2/1.5 and 1.5/2) and Re = 20,000 were in good agreement with the analytical results of Ibrahim and Gomaa (2009).