Developes procedure for calculating air infiltration rates due to wind pressures on the exterior walls of buildings, assuming no chimney and mechanical ventilation effects. Assumes resistance to internal air flow is small. Using results of wind tunnel test, presents calculations showing the significant effects a single neighbouring building can have on the infiltration rates. Relative building heights, distance between buildings and wind direction are varied, and both uniform and shear flows are considered. Results show that depending on the particular two-body configuration, a neighbouring building can have a favourable or adverse effect on the infiltration rate.