Free convection heat transfer from a vertical array of five horizontal isothermal cylinders separated by flow diverters is investigated experimentally through a Mach-Zehnder interferometer. Flow diverters with widths of 1, 2, and 3 cylinder-diameter are placed midway between the cylinders with a 45-degree inclination angle. The cylinders vertical center to center spacing is kept constant to three-cylinder diameter. The experiments are carried out for various Rayleigh numbers based on the cylinder diameter in the range of 10(3) to 2.5 x 10(3) and for different flow diverter width. It is observed that the flow diverters enhance the heat transfer of the array from 10% to 27%, depending on their width. By increasing the width of the diverters and the Rayleigh number, enhancement of the heat transfer from the array increases.