Purpose: To describe a proximal extension of a failed chimney endovascular aneurysm sealing repair (chEVAS) using a chEVAS-in-chEVAS procedure in 2 cases with successful treatment outcome at 2-year follow-up. Case Report: Two patients with an infrarenal abdominal aortic aneurysm were treated with an elective chEVAS procedure with 1 chimney stent for a unilateral renal artery. At 18 and 24 months, respectively, both patients showed aneurysm growth with an associated decrease in proximal seal. Both patients were treated with a secondary chEVAS procedure, consisting of chimney stent-graft placement in the contralateral renal and the superior mesenteric arteries combined with proximal extension of the in situ chimney stent-graft and the Nellix stents. Two-year follow-up demonstrated successful aneurysm exclusion with a patent stent configuration. Conclusion: A type Ia endoleak after chEVAS can be successfully repaired with a chEVAS-in-chEVAS procedure.