The present study is devoted to an effect of a supercooled liquid region on crystallization behaviour of the Al85RE8Ni5Co2 metallic glasses produced by rapid solidification of the melt. The Al85RE8Ni5Co2 amorphous alloys can be divided into two groups depending on whether they show glass-transition on heating or not. Under annealing at the temperature above the glass-transition or under continuous heating at high enough heating rate, most of the Al-RE-Ni-Co glasses exhibiting formation of the supercooled liquid region primarily crystallize by precipitation of the nanoscale alpha-Al particles, Al-RE-Ni-Co alloys having no glass transition form intermetallic compounds primarily or corporately with alpha-Al. Amorphous alloys exhibiting no glass-transition crystallize equally at different modes studied. However, crystallization of the Al-RE-Ni-Co metallic glasses below glass-transition temperature follows different transformation mechanism. During isothermal annealing below glass-transition temperature an unknown metastable phase is formed conjointly with alpha-Al. Although trunsformation mechanism looks similar to an eutectic one some differences are found.