This paper is concerned with an accurate prediction of the effects of adjacent structures on the blast loads on a building in urban terrain. Blast loadings on structures have typically been evaluated using empirical relationships. These relationships assume that there are no obstacles between the charge and the target. In real situations, the actual blast loads can either be reduced due to shadowing by other buildings or can be enhanced due to the presence of other buildings in the vicinity. Results of the numerical simulations presented in this study for multiple buildings in an urban environment have demonstrated the importance of accounting for adjacent structures when determining the blast loads on buildings. An approach to determining the enhancement factors is described.