Scavenging efficiency of polydisperse soot particles in two size ranges (submicron to 10-mu-m and submicron to 1-mu-m) by ice crystals was investigated in the laboratory. Ice crystals were grown, evaporated or kept at ice saturation under controlled temperature, saturation and air flow velocity in a dynamic thermal diffusion chamber in the presence of polydisperse soot particles. Crystals were also grown in a supercooled cloud in a cold box filled with polydisperse soot. Scanning electron micrographs of ice crystal replicas revealed that soot particles were scavenged most effectively by the growing ice crystals in the submicron to 10-mu-m range. In the submicron range growing crystals were more effective scavengers than the ones which were kept at ice saturation, evaporating ice crystals had the least collection efficiency.