This is a multi-center, open-label, Phase I study of Obatoclax administered in combination with bortezomib in 3-week cycles to patients with relapsed or refractory Mantle Cell Lymphoma. Treatment may be administered on an outpatient basis. No investigational or commercial agents or therapies other than those described herein may be administered with the intent to treat the patients's malignancy. Supportive care measures including those directed at controlling symptoms resulting from Mantle Cell Lymphoma are allowed.