The kinetics and mechanism of bainite transformation have been studied in Fe-Cr-Mo-V-Ti-C steel high speed dilatometry backed by thermodynamic analysis. The complete transformation of austenite, however, has not occurred at any reported temperature. Obtained results confirm the incomplete reaction phenomenon with the cessation of the bainite transformation well before the paraequilibrium is achieved. These experimental data indicate that bainitic ferrite is formed by a displacive transformation mechanism, but soon afterwards, excess of carbon is patitioned into the residual austenite. The results are discussed in terms of the mechanism of bainite transformation.