The invention relates to processes for the preparation of highly concentrated, liquid formulations comprising at least one anti-EGFR antibody and/or one of its variants and/or fragments, in particular monoclonal antibodies against the EGF receptor, particularly preferably of Mab C225 (cetuximab) and Mab h425 (EMD 72000), by ultrafiltration. The invention furthermore relates to highly concentrated, liquid formulations of anti-EGFR antibodies, in particular of monoclonal antibodies against the EGF receptor, particularly preferably Mab C225 (cetuximab) and Mab h425 (EMD 72000) and/or variants and/or fragments thereof, characterised in that the highly concentrated, liquid formulations have a content of anti-EGFR antibodies of 10-250, preferably 50-180 mg/ml, particularly preferably of 100-150 mg/ml, and to the use thereof.