The invention provides peptides of about 9-12 amino acids having a sequence derived from the interferon binding site of the IFNAR1 chain of the Type 1-interfereon (Type 1-IFN) receptor for use as a Type 1-IFN antagonist. In particular, the invention provides peptides having the 9 mer sequence FSSLKLNVY (Sequence ID no. 1) and analogues thereof for use as Type 1-IFN antagonists. Particularly preferred for this purpose is the peptide of Sequence ID no. 1 and analogues thereof including Sequence ID no. 1 having an additional asparagine residue (N) at the C-terminus and/or additional glutamic acid residue (E) at the N-terminus.