Measurements of turbulent natural-convection flow over a two-dimensional, vertical, forward-facing step are reported. Laser Doppler velocimeter and cold-wire anemometer were used to, respectively, measure simultaneously the time-mean turbulent velocity and temperature distributions and their turbulent fluctuation intensities. The upstream and downstream walls and the step itself were heated to a uniform and constant temperature. The experiment was carried out for a step height of 22 mm and a temperature difference between the heated walls and the free stream (ambient air), DeltaT, of 30 degreesC (corresponding to a local Grashof number Gr(xi) = 6.45 x 10(10)). Measurements of the time-mean velocities and temperature distributions along with their turbulent fluctuation intensities are presented at various locations upstream and downstream of the forward-facing step. The present results reveal that the maximum local Nusselt number occurs in the vicinity of the reattachment region and it is approximately two-and-a-half times that of a flat-plate value at similar flow and thermal conditions. These measurements can serve as a test case for turbulence models in predicting numerically the flow and heat transfer characteristics in this geometry and these experimental conditions.