This study aims to develop a technique for preparing stable magnetorheological (MR) fluids using a low-molecular organogelator, N, N', N '', N"'-1,2,4,5-tetra alkyl/alkenyl pyromellitamide (PMDA-R), with poly-alpha-olefin as a base oil. The rheological properties and stability of the MR fluids prepared were evaluated through three stability tests: an oil separation test, a static stability test, and a centrifugal separation test. PMDA-R with oleyl and 2-ethylhexyl was found to markedly improve the stability of MR fluids. The relation between the results of the centrifugal separation test and the rheological properties was also examined.