Observing the effects of Arg-Gly-Asp-Ser(RGDS) peptides on the actin organization and apoptosis in human glomerular mesangial cells, in order to explore the interaction mechanism of extracellular matrix (ECM)-integrin receptor-cy-toskeleton. Methods The alterations of actin microfilaments in glomerular mesangial cells were observed under laser scanning confocal microscope. And DNA electrophoresis and flowcytometry were used for assessing apoptosis. Results After two hours of incubation with RGDS peptides, some of the attached glomerular mesangial cells began to round up, with a prominent marginaliza-tion of the actin microfilaments which were bundled in thick aggergates to one edge of the cell. Later these cells detached and floated in the culture medium.The above sequently-occuring changes showed a time-dependent pattern. After ten hours of incubation with RGDS peptide, most of the cells had detached, and features of apoptosis appeared in them, such as inter-nucleo-somal DNA fragmentation and decreased DNA content. Conclusion RGDS tetrapeptide can disrupt the organization of cytoplasmic actin mi-crofilament, inhibit the attachment of the cultured glomerular mesangial cells and cause apoptosis in them.