The present invention provides antagonizing antibodies, antigen-binding portions thereof, and aptamers that bind to proprotein convertase subtilisin kexin type 9 (PCSK9). Also provided are antibodies directed to peptides, in which the antibodies bind to PCSK9. The invention further provides a method of obtaining such antibodies and antibody-encoding nucleic acid. The invention further relates to therapeutic methods for use of these antibodies and antigen-binding portions thereof to reduce LDL-cholesterol levels and/or for the treatment and/or prevention of cardiovascular disease, including treatment of hypercholesterolemia.