The LDL receptor (160 kD mature or glycosylated receptor; 120 kD precursor or unglycosylated receptor) plays a key role in cellular cholesterol homeostasis. The antibody to LDLR reacts specifically with human LDLR and is suitable for use in flow cytometry and immunoblotting. The antibody does not inhibit binding of LDL. In immunoblotting, the antibody recognizes the 160 kD band of LDLR and a 120 kD band of the LDLR precursor from fibroblasts, hepatocytes, and monocytic cells cultured in the presence of lipoprotein-deficient serum.