FeSi2 alloys doped with Mn and Co (p-type Fe0.926Mn0.074Si2, n-type Fe0.980Co0.020Si2) were prepared by vacuum induction melting. The ingots were pulverized in a jet-mill, and the powders were granulated by spray drying method using aqueous polyvinyl alcohol ( PVA) binder in order to investigate the possibility of production on a large scale. The powders granulated exhibited excellent characteristics of flowability, leading to the smooth feeding into a die cavity in compacting. The powders obtained were compacted at a pressure of 98 MPa. It was debindered at 723 K for 1 h and sintered at 1423 K for 5 h in a hydrogen atmosphere, so that the residual carbon and oxygen contents in a sintered body approached to those in the starting powder. Subsequently it was annealed at 1113 K for 100 h in an argon atmosphere, to produce the semiconducting beta-FeSi2 phase. The thermoelectric figures of merit (Z) for optimum p- and n-type FeSi2 are 1.75 x 10(-4) (K-1) and 2.0 x 10(-4) (K-1) at about 900 K, respectively, which agree roughly with those obtained by Tani and Kido for FeSi2 materials prepared by the spark plasma sintering method. It indicates that the spray drying method leading to the production on a large scale is available for the fabrication of the thermoelectric FeSi2 materials. (C) 2003 Kluwer Academic Publishers.