This paper presents an analytical investigation on the required separations between adjacent buildings to avoid pounding during earthquakes. Five wall buildings, having 3, 6, 10, 15, and 25 storeys, were designed for three different seismic zones in Canada: Montreal, Vancouver, and Prince Rupert. For each zone, an ensemble of code compatible ground motions was identified. Nonlinear time-step dynamic analyses were performed to determine the separations to avoid pounding between each building pair under each earthquake. The required separations, obtained by subtracting the time-histories of lateral displacements between adjacent floor levels, were compared with the requirements of the static method of the National Building Code of Canada. The results indicate that the static method of the code grossly overestimates the required separations. This is to be expected, since the static code procedure does not take full account of the intervening variables (periods, responses, and phases between building motions) which characterize the ground motion and building properties when determining the separation distances. A simplified spectral difference procedure is proposed for inclusion in future editions of the code. Key words: dynamics, earthquake, gap, pounding, seismic, separations.