A new inspection system using laser scattering was developed to characterize bulk microdefects in intrinsic gettering processed Si wafers. The density profiles of bulk microdefects and the width of the denuded zone in Si wafers were measured by this system without any etching treatment. The minimum size observed, as a particle, was estimated at several tens of nm in diameter by comparing a scattering image with a transmission electron microscope observation. From an analysis of the scattering intensity, differences of up to 10% in diameter were recognizable.