The kinetics of slow irreversible aggregation of monodisperse polystyrene latex spheres is investigated by means of the transient electric birefringence (TEE) technique, The amplitude of the TEE signal is connected with the anisotropy of fractal clusters; the decay of the signal after the electric field is switched off contains information about average cluster size and size distribution. The TEE results are compared with static and dynamic light scattering data,