The hydrodynamic behavior of an iron and iron-sand beds is investigated in the presence of an externally applied uniform magnetic field collinear with gas flow. In addition heat-transfer measurements from a horizontal electrically heated probe are conducted. The gas Velocity is varied over a wide range to bring about different: regimes for different magnetic-held intensity values in the range 0-9641 A m(-1). The minimum bubbling velocity and heat-transfer coefficient values are discussed and correlated. It is found that bed voidage and segregation of admixture components play a very important role in establishing the, hydrodynamic and heat-transfer characteristics of the magnetofluidized beds. (C) 1997 Elsevier Science Ltd.