We combine a numerical, boundary element method with analytical techniques to predict the motion of isolated, nonspherical particles moving at low Reynolds number through a Newtonian fluid. The boundary element method is used to determine the constant components of the resistance matrix (a geometry-specific matrix relating a particle＇s linear and angular velocities to the applied forces and torques). Once the resistance matrix has been constructed, direct simulation of the translation and rotation of the particle in streaming flow can be performed. Applications in aerosol characterization have led us to do this analysis for agglomerates of spheres, as well as flake-like particles. We obtain excellent agreement with the limited, published, experimental data.