The goal of therapy for traumatic carotid-cavernous fistula (TCCF) is the elimination of fistula while maintaining patency of the parent artery. The treatment for TCCF has evolved from surgery to endovascular management using detachable balloons, coils, liquid embolic agents, covered stents, or flow-diverter stent through arterial or venous approaches. Despite the withdrawal of detachable balloons from the market in the United States since 2004, transarterial embolization with detachable balloons has currently remained the best initial treatment for TCCF in several countries. However, the pseudoaneurysm formation following transarterial detachable balloon embolization has rarely been observed in long-term follow-up. To determine the occurrence and long-term follow-up of pseudoaneurysm after transarterial detachable balloon for TCCF. Between January 2009 and December 2019, 79 patients diagnosed with TCCF were treated using detachable latex balloons (GOLDBAL) of four sizes. Pseudoaneurysm sizes were stratified into five grades for analysis. Initial and follow-up assessments involved computed tomography angiography at 1 month, 6 month, 1 year, and longer intervals for significant cases. Clinical follow-ups occurred semi-annually for 2 years, then annually. Factors analyzed included sex, age, fistula size and location, and balloon size. In our cohort of 79 patients treated for TCCF, pseudoaneurysms formed in 67.1%, with classifications ranging from grade 0 to grade 3; no grade 4 or giant pseudoaneurysms were observed. The majority of pseudoaneurysms did not progress in size, and some regressed spontaneously. Calcifications developed in most large pseudoaneurysms over 5-10 years. Parent artery occlusion occurred in 7.6% and recurrent fistulas in 16.5%. The primary risk factors for pseudoaneurysm formation were identified as the use of specific balloon sizes, with balloon SP and No. 6 significantly associated with its occurrence (P = 0.005 and P = 0.002, respectively), whereas sex, age, fistula size, location, and the number of balloons used were not significant predictors. Pseudoaneurysm formation following detachable balloon embolization for TCCF is common, primarily influenced by the size of the balloon used. Despite this, all patients with pseudoaneurysms remained asymptomatic during long-term follow-up.