Assess electromagnetically guided in situ fenestration of juxtarenal aortic stent grafts in an in vivo model. Using a newly developed electromagnetic guidance system together with a modified, electromagnetically guidable catheter with steerable tip, an electromagnetically trackable guidewire and a custom in situ fenestrateable stent graft, a series of seven animal experiments was performed. In a swine model, stent grafts were placed juxtarenally, covering the renal arteries. Subsequently, the perfusion of the renal arteries was restored using electromagnetically guided in situ fenestration of the graft at the renal ostia followed by covered stent placement. Intervention times and technical success were assessed. The individual components were successfully combined for the animal experiments. Thirteen of fourteen fenestration experiments in seven animals were successful in restoring perfusion through in situ fenestration. Fenestration (catheter introduction—guidewire placement in renal artery across graft) could be achieved in on average 10.5 ± 9.2 min, and subsequent covered stent placement (guidewire placement—covered stent placement) took on average 32.7 ± 17.5 min. No significant differences between left and right side reperfusion times could be detected. Reperfusion in <30 min was achieved in 3/14 attempts. Electromagnetically navigated in situ aortic fenestration for juxtarenal aortic stent grafts was feasible in a healthy animal model. Identified remaining challenges were: shortening the procedure to avoid long warm ischemia times, using an aortic aneurysm animal model, and improving the stability of the stent graft material.