An experimental study was made of the unsteady pressures induced on a two-dimensional airfoil by the rotation of an elliptical cylinder located behind and beneath the airfoil trailing edge. The experiment was conducted in a low Mach number flow for reduced frequencies based on airfoil semichord up to 6.4. Mean pressures and phases and amplitudes of the fundamental harmonic were measured and compared to predictions made using thin airfoil theory and the measured unsteady upwash produced by the rotating cylinder alone. Mean difference pressures were found to be in good agreement with the predictions. The pressure difference approached zero as the trailing edge was approached. Qualitative agreement between data and thin airfoil theory was found for the oscillating component except near the trailing edge where a difference in the phase was found.