Objective Despite technical advances of fenestrated and branched endografts, endovascular exclusion of aneurysms involving renal, visceral, and/or supra-aortic branches remains a challenge. In situ fenestration (ISF) of standard endografts represents another endovascular means to maintain perfusion to such branches. This study aimed to review current indications, technical descriptions, and results of ISF. Method A review of the English language literature was performed in Medline databases, Cochrane Database, Web of Science, and Scopus using the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. Sixty-seven relevant papers were selected. Thirty-three papers were excluded, leaving 34 articles as the basis of the present review. Results Most experimental papers evaluated ISF feasibility and assessed the consequences of ISF on graft fabric. Regarding clinical papers, 73 ISF procedures have been attempted in 58 patients, including 26 (45%) emergent and three (5%) bailout cases. Sixty-five (89%) ISF were located at the level of the arch, and eight (11%) in the abdominal aorta. Graft perforation was performed by physical, mechanical, or unspecified means in 33 (45%), 38 (52%), and two vessels (3%), respectively. ISF was technically successful in 68/73 (93%) arteries. At 30 days, two (3.4%) patients died in the setting of an aorto-bronchial fistula and an aorto-oesophageal fistula, respectively. No post-operative death, major complication, or endoleak was described as secondary to the ISF procedure. With follow-up between 0 and 72 months, four (6.9%) late deaths were noted, unrelated to the aorta. One (1.7%) LSA stent was stenosed without symptoms. Conclusions Although there may be publication bias, multiple techniques were described to perform ISF with satisfactory short-term results. Long-term data remain scarce. Aortic endograft ISF is an off-label procedure that should not be used outside emergent bailout techniques or investigational studies. A comparison with alternative techniques of preserving aortic side branches is needed.