The phase transformations in an Fe-8Al-30Mn-1.5Si-1.5C alloy has been investigated by means of transmission electron microscopy. In the as-quenched condition, the microstructure of the alloy was austenite phase containing fine (Fe,Mn)(3)AlC carbides. The fine (Fe,Mn)(3) AlC carbides were formed during quenching by a spinodal decomposition. When the as-quenched alloy was aged at temperatures ranging from 550 to 1000 degreesC, the phase transformation sequence as the aging temperature increased was found to be (Fe,Mn)(3)AlC carbide + D0(3) --> (Fe, Mn)(3)AlC carbide + B2 --> (Fe, Mn)(3)AlC carbide + alpha --> gamma. This transformation has never before been observed in the Fe-Al-Mn-C and Fe-Al-Mn-Si-C alloys.