The present paper describes heat transfer around two side-by-side closely arranged circular cylinders. The flows around two circular cylinders in a side-by-side arrangement can be classified into three flow patterns according to the gap between the two cylinders. The heat transfer characteristics of the cylinders in each flow regime were experimentally investigated. The diameter of the circular cylinders was 40 mm and the gap between the two cylinders varied from 4 mm to 40 mm. The free stream velocity ranged from 4 m/s to 24 m/s, resulting in Reynolds nos. ranging from $1.1×104$ to $6.2×104$. The local heat transfer coefficient of both cylinders was measured. The overall Nusselt no. of the two cylinders was found to be minimum at $G/D(=gap/diameter)=0.4$, which is the minimum drag coefficient condition of the two cylinders, too.

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