The invention relates to FGF receptor-activating N-sulfate oligosaccharides having Formula (I), wherein R, R, R, and R are -OSO- or hydroxyl groups, R is an -O-alkyl group or a monosaccharide having Formula (II), R is a disaccharide having Formula (III), R is a disaccharide having Formula (IV), R is a hydroxyl group or a disaccharide having Formula (VI), and R is a hydroxyl or -O-alkyl group or a disaccharide having Formula (VII), where R is an -O-alkyl group. The invention further relates to the preparation of said oligosaccharides and to the therapeutic use thereof.