Background - Retrograde type A aortic dissection has been deemed a rare complication after endovascular stent graft placement for type B dissection. However, this life-threatening event appears to be underrecognized and is worth being investigated further. Methods and Results - Eleven of 443 patients developed retrograde type A aortic dissection during or after stent grafting for type B dissection from August 2000 to June 2007. Of these 11 patients, 3 had Marfan syndrome. The Kaplan-Meier estimate of the rate of freedom from this event at 36 months is 97.4% (95% confidence interval, 0.95 to 0.99). The new entry was located at the tip of the proximal bare spring of the stent graft in 9 patients, was within the anchoring area of the proximal bare spring in 1, and remained unknown in 1 patient. Eight patients were converted to open surgery, and 2 received medical treatment. One patient suddenly died 2 hours after the primary stent grafting, and 2 died within 1 week after the surgical conversion, so mortality reached 27.3%. During the follow-up from 3 to 50 months, type I endoleak was identified in 1 patient 3 months after the surgical exploration and disappeared at 6 months. Conclusions - Retrograde type A aortic dissection after stent grafting for type B dissection appears not to be rare and results from mixed causes. Fragility of the aortic wall and disease progression may predispose to it, whereas stent grafting-related factors make important and provocative contributions. Avoiding aortic arch stent grafting in Marfan patients, preferably selecting the endograft without the proximal bare spring for patients with a kinked aortic arch or with Marfan syndrome (if endografting is used), improving the device design, and standardizing endovascular manipulation might lessen its occurrence. © 2009 American Heart Association, Inc.