Shock-tunnel measurements are reported of skin friction with supersonic hydrogen-air combustion in a constant area duct. A floating-element skin-friction gauge was used, in which the shear force was applied directly to a piezoceramic measuring element. The experiments were conducted at stagnation enthalpies of 5.7 and 6.8 MJ kg(-1), a precombustion Mach number of similar to 4.5, and with a maximum duct Reynolds number of 1.3 x 10(7). The measurements showed that, although supersonic combustion caused the skin friction to fluctuate with time, it did not affect the mean value of the skin friction coefficient, and this mean value could be predicted using existing turbulent: boundary-layer theory. Measurements of heat transfer also established that Reynolds analogy could be used in both the fuel-off and fuel-on flows.