The invention relates to specific Antibody-Drug-Conjugates (ADCs) with KSP inhibitors and anti- CD 123 -antibodies, to the use of these conjugates for the treatment and/or prophylaxis of diseases and to the use of these conjugates for preparing medicaments for treatment and/or prevention of diseases, in particular hyperproliferative and/or angiogenic disorders such as, for example, cancer diseases. Such treatments can be carried out as monotherapy or else in combination with other medicaments or further therapeutic measures.