Background Thromboembolic events and intraoperative rupture are the most frequent neurologic complications of intracranial aneurysm coiling. Their frequency has not been evaluated in recent series. Purpose To provide an analysis of complications, clinical outcome, and participant and aneurysm risk factors after aneurysm coiling or balloon-assisted coiling within the Analysis of Recanalization after Endovascular Treatment of Intracranial Aneurysm, or ARETA, cohort. Materials and Methods Sixteen neurointerventional departments prospectively enrolled participants treated for ruptured and unruptured aneurysms between December 2013 and May 2015. Participant demographics, aneurysm characteristics, and endovascular techniques were recorded. Data were analyzed from participants within the overall cohort treated with coiling or balloon-assisted coiling for a single aneurysm. Rates of neurologic complications were analyzed, and associated factors were studied by using univariable analyses (Student t test, χ2 test, or Fisher exact test, as appropriate) and multivariable analyses (logistic regressions). Results A total of 1088 participants (mean age ± standard deviation, 54 years ± 13; 715 women [65.7%]) were analyzed. Thromboembolic events and intraoperative rupture were reported in 113 of 1088 participants (10.4%) and 34 of 1088 participants (3.1%), respectively. Poor clinical outcome (defined as modified Rankin Scale score of 3-6) was reported in 29 of 113 participants (25.7%) with thromboembolic events and in 11 of 34 participants (32.4%) with intraoperative rupture (P = .44). Factors associated with thromboembolic events were female sex (odds ratio [OR], 1.7; 95% confidence interval [CI]: 1.1, 2.8; P = .02) and middle cerebral artery location (OR, 1.9; 95% CI: 1.2, 3.0; P = .008). Factors associated with intraoperative rupture were anterior communicating artery location (OR, 2.2; 95% CI: 1.1, 4.7; P = .03) and small aneurysm size (OR, 3.0; 95% CI: 1.5, 6.3; P = .003). Conclusion During aneurysm coiling or balloon-assisted coiling, thromboembolic events were more frequent than were intraoperative rupture. Both complications were associated with poor clinical outcome in a similar percentage of participants. Risk factors for thromboembolic events were female sex and middle cerebral artery location. Risk factors for intraoperative rupture were small aneurysm size and anterior cerebral or communicating artery location. © RSNA, 2020.