Abstract: A lactic acid based hot-melt adhesive with an amorphous lactic acid oligomer tackifier. A hot-melt adhesive (HMA) includes: a lactic acid and caprolactone copolymer resin, a crystalline lactic acid oligomer wax, and said amorphous lactic acid oligomer tackifier, characterized in that the amorphous lactic acid oligomer tackifier includes an amorphous polymerisation product of a) lactic acid monomer and b) a multifunctional polymerization initiator containing three or more hydroxy and/or amino groups. The use of the amorphous lactic acid oligomer tackifier in a lactic acid-based hot-melt adhesive, to a method for adhering substrates together using a hot-melt adhesive including said amorphous lactic acid oligomer tackifier, and to a specific amorphous lactic acid oligomer tackifier and a method of its preparation.