Kinetics and processes of the B2-DO₃ordering in the Fe₃Al intermetallic compound were investigated using transmission electron microscopy. The overall ordering seemed to occur as in the homogeneous nucleation and growth process. However, the initial stage of the ordering also revealed the characteristics of the continuous process. The heterogeneous nucleation of the DO₃ phase was not observed for several aging and quench temperatures. Excess vacancies enhanced the growth rate of the DO₃ antiphase domains.