Background: There are limited data to guide the optimum approach to patients presenting with angina after coronary artery bypass grafting (CABG). Although often referred for invasive angiography, the effectiveness of this is unknown; angina may also result from diffuse distal or micro-vascular coronary disease and it is not known how often targets for intervention are identified. Methods: Retrospective review of 50,460 patients undergoing angiography in East Denmark between January 2010 and December 2014. Clinical and procedural data were prospectively stored in a regional electronic database. Follow-up data were available for all patients, by means of records linked to each Danish social security number. Results: In patients with prior CABG and stable angina (n = 2,309), diagnostic angiography led to revascularization in 574 (24.9%) cases. Chronic kidney disease (HR 1.93 [1.08–3.44], P = 0.027), significant angina (HR 1.49 [1.18–1.88], P = 0.006 for angina class ≥ II, and HR 2.04 [1.61–2.58], P < 0.001 for angina class ≥ III) and a positive pre-procedural stress test (HR 2.56 [1.42–4.60], P < 0.001) were independent predictors of revascularization. Stress testing was, however, used less frequently than in patients without prior CABG (17.2% vs. 24.2%, P < 0.001). The positive predictive values for subsequent revascularization were 47.8%, 51.4%, and 66.9% for exercise ECG, stress echocardiography, and myocardial perfusion scintigraphy (MPS), respectively. Conclusions: Invasive angiography leads to revascularization in a quarter of patients with angina and prior CABG; the threshold for referral may be too low. Non-invasive stress testing predicts the need for revascularization but appears underused and MPS, in particular, may better identify patients likely to require revascularization.