The present invention relates to polypeptides which are covalently bound to molecular scaffolds such that two or more peptide loops are subtended between attachment points to the scaffold. In particular, the invention describes peptides which are high affinity binders of membrane type 1 metalloprotease (MT1-MMP). The invention also describes drug conjugates comprising said peptides, conjugated to one or more effector and/or functional groups which have utility in imaging and targeted cancer therapy.