Characteristic free cells with Russell bodies native to the coelomic cavity of newts were examined by both transmission and scanning electron microscopies. Surface morphology of a Russell cell exhibited close resemblance to the appearance of a monocyte. Bipolar processes of the cell were actually thin, flattened cytoplasmic extensions, which were quite polymorphous membrane architecture. Cross-sectioned ultrastructure demonstrated that the greatly distended vacuole occupied most of the cell volume and cytoplasm seemed to be thinly expanded by the vacuole. Numerous filaments were included in the conspicuous vacuoles, which morphology was similar to the collagenous fiber. Cross-sectiion of the filament viewed a tubular structure with consistent diameter of 40 to 50 nm. Density of intravacuolar fibriles varied possibly by the maturity of Russell cells. The present observation demonstrated that Russell bodies of newt free cells have a quite dissimilar character to those of mammalian plasma cells.