Antagonism of the calcitonin gene-related peptide (CGRP) receptor may be a useful approach for migraine treatment. Selective PEGylated peptide antagonists to the CGRP receptor are described, derived from CGRP(8–37) with polymer derivatization at an engineered lysine-25 residue. Potent PEGylated peptides with improved pharmacokinetics were identified through peptide side-chain modification to mitigate metabolic liabilities. PEGylated Ac-Trp-[Cit11,18,hArg24,Lys25,Asp31,Pro34,1-Nal35]CGRP(8–37)-NH2, 9, elicits a dose-dependent reduction of intradermal CGRP-induced local blood flow in rodents with an ED50 of 0.52 mg kg−1 without any overt adverse effects. © 2013 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 100: 422–430, 2013.