We present results for simulations of electromagnetic field propagation at 900 MHz in the presence of groups of people. The starting geometry of humans is modeled using combination of programs MakeHuman and Blender. It is then imported into 3-D electromagnetic numerical solver based on surface integral-equation formulation, higher-order basis functions and Galerkin testing, accelerated using graphical processing units (WIPL-D). The objective of simulations is to obtain the attenuation of electromagnetic field propagating through human crowds. The initial experimental verification is done and the results are presented.