Pile foundations are often subjected to both vertical and lateral loads. The current design practices assume that the effect of these two loads is independent of each other and hence the pile design is carried out separately for vertical and lateral loads. The conventional methods for analysis of piles based on sub-grade reaction methods also do not account for the interaction between the vertical and lateral loads. The influence of vertical loads on the lateral response of piles installed in sandy soils is brought out in this paper through 3-dimensional finite element analyses. In the numerical model, the pile was treated as a linear elastic material and the soil was idealized using the Drucker-Prager constitutive model with a non-associated flow rule. The results from the analysis of single piles under pure lateral loads and combined vertical and lateral loads are presented in this paper. The influence of related parameters, viz. sequence of load application, shear strength (angle of internal friction and dilation angle) of soil, pile head fixity and pile slenderness (L/B) ratio have also been studied in the paper. © 2006 Elsevier Ltd. All rights reserved.