The aim of this study was to prospectively evaluate the feasibility and safety of intraoperative invasive coronary angiography (ICA) following coronary artery bypass grafting using a mobile angiography C-arm. Between August 2020 and December 2021, 18 patients were enrolled for intraoperative ICA following coronary artery bypass grafting. After skin closure, ICA was performed including angiography of all established bypass grafts via a mobile angiography system by an interventional cardiologist. Data on graft patency, stenosis, and kinking were assessed. Grafts were rated on an ordinal scale ranging from very poor (1) to excellent (5). Furthermore, the impact of ICA compared with flow measurement was assessed using the ordinal Likert scale ranging from (I) worse to (V) much better. The ICA was considered better (V) compared with transient flow measurement in 38 (93%) and comparable (III) in 3 (7%) distal anastomoses. ICA impacted clinical or surgical decision-making in three patients (17%). In one patient, dual antiplatelet therapy for 6 months was initiated and rethoracotomy was needed in two (11%) patients with bypass graft revision and additional bypass grafting for graft occlusion. There were no cerebral and distal embolic events or access vessel complications observed and no postoperative acute kidney injury occurred. Intraoperative angiography after coronary bypass grafting is safe. Using a mobile angiographic device, graft patency, and function assessment was superior to transit time flow measurement leading to further consequences in a relevant number of patients. Therefore, it has the potential to reduce postoperative myocardial injury and improve survival.