This study was carried out to determine the contribution of altered vascular MMP-2 expression to systemic vascular reactivity in the setting of prolonged hypoxia. Rats and mice were exposed to hypoxia (10% and 8% O₂, respectively) or normoxia (21% O₂) for 16 hours, 48 hours, or 7 days. Aortae and mesenteric arteries were either mounted in organ bath myographs or frozen in liquid nitrogen. MMP-2 inhibition with cyclic CTTHWGFTLC (CTT) reduced contraction to phenylephrine (PE) in aortae and mesenteric arteries from rats exposed to hypoxia for 7 days, but not in vessels from normoxic rats. Similarly, CTT reduced contraction to big endothelin-1 (big ET-1) in aortae from rats exposed to hypoxia for 7 days. Responses to PE were reduced in hypoxic MMP-2^-/- mice compared to MMP-2^+/+ mice. Increased contraction to big ET-1 after hypoxia was observed in MMP-2^+/+ mice, but not MMP-2^-/- mice. Rat aortic MMP-2 and MT1-MMP protein levels and MMP activity were increased after 7 days of hypoxia. Rat aortic MMP-2 and MT1-MMP mRNA levels were increased in the deep medial vascular smooth muscle. We conclude that hypoxic induction of MMP-2 expression potentiates contraction in systemic conduit and resistance arteries. This may preserve the capacity to regulate the systemic circulation in the transition between the alterations in vascular tone and structural remodeling that occurs during prolonged hypoxic epochs.