The growth kinetics of undercooled melts of soft magnetic Fe 30 at% Co and Fe 50 at% Co alloys was investigated using the electromagnetic levitation technique. It could be shown that primary solidification of the metastable BCC phase is favoured by exceeding critical undercooling levels of 65–80 K and 140–160 K, respectively. The growth velocity of the metastable phase is considerably lowered compared to the stable one which agrees very well with the model calculations of the dendrite growth.