Hepatitis A virus particles (d = 27 nm) were successfully accumulated and trapped in a microfluidic system by means of a combination of electrohydrodynamic flow and dielectrophoretic forces. Electric fields were generated in a field cage consisting of eight microelectrodes. In addition, high medium conductance (0.3 S/m) resulted in sufficient Joule heating and the corresponding spatial variation of temperature, density, and permittivity to induce electrohydrodynamic flow in the vicinity of the field cage. Flow vortices transport particles toward the center of the field cage, where dielectrophoretic forces cause permanent entrapment and particle aggregation. Spatial distribution of temperature, density, and permittivity as well as resulting flow patterns were modeled numerically and are in good agreement with experimental results. This accumulation scheme might be applicable to sample concentration enhancement in biosensor applications.