Local heat transfer coefficients have been measured on a single pin fin (a short cylinder mounted across a duct), on a pin fin in the wake of another and on a pin fin in a bank of in-line and staggered arrangements. The pin fins were two diameters in length and were arranged with a pitch to diameter ratio of 2.0. The Reynolds number was 23,000. Uniform heat flux boundary conditions were obtained by electrically heating a thin gold film on the surface while measuring an isotherm on the surface with a liquid crystal. The measurements show the effect of the duct turbulence, of flow separation and of impingement on the distribution of heat transfer.