New morphological trait, "Hairy leaf", of mangel beet has been picked out. Dominant character and monogenic inheritance of the trait were found. Comparative analysis of manifestation of this trait in mangel and sugar beets was done. It is shown that the gene of "hairiness" (Hl) in sugar beet is not allelic to the Hlvar gene in mangel beet. This trait can be used as a marker in selection-genetical investigation.