Unsteady laminar convective heat transfer from two isothermal cylinders of tandem arrangement is numerically investigated. The numerical simulations were carried out by the commercial CFD software-FLUENT (R). The working fluid is air. The analysis is carried out for the Reynolds numbers of 100 and 200 and for center-to-center distance ratio, L/D, of 2, 3, 4, 5, 7 and 10. The flow parameters such as the lift and drag coefficients and Strouhal number are also obtained and compared with those of available in the literature. The vorticity and isotherms were generated to interpret the flow and heat transport visualization. The mean and local Nusselt numbers for the upstream and downstream cylinders were obtained. It is found that the mean Nusselt number of the upstream cylinder approaches to that of an single isothermal cylinder for L/D > 4 and the mean Nusselt number of the downstream cylinder is about 80% of the upstream cylinder. (C) 2008 Elsevier Inc. All rights reserved.