With the introduction of high-sensitivity troponin (hsTNI) assays, the clinical significance unstable angina (UA) has become uncertain. We hypothesized that impaired left ventricular (LV) two-dimensional speckle-tracking echocardiography (2D-STE)-derived peak global longitudinal strain (GLS) was able to exclude the presence of significant coronary artery disease (CAD) in UA patients without prior cardiovascular (CV) events and with a normal LV ejection fraction (LVEF). From a cohort of 200 patients admitted with UA, we selected 61 patients without prior CV events and with a normal LVEF; of these, 48 (79%) underwent invasive coronary angiography (ICA) and 24 (39%) had at least ≥ 1 significant stenosis. 2D-STE LV GLS analysis was performed offline using a dedicated automated software program. The mean patient age was 61 ± 12 years and 66% were male. Among the 48 patients selected to undergo ICA, those without significant CAD had a better 2D-STE GLS (− 19.4 vs. − 15.9%, P < 0.001). A cutoff of − 17.5% had a sensitivity of 87% and a specificity of 82% for differentiating UA patients without significant stenosis (AUC 0.86, P < 0.001). Patients who did not undergo ICA had a better GLS (− 20.2 vs. − 17.7%, P = 0.017). 2D-STE GLS had a significantly better discriminative power compared with LVEF (P < 0.001) and the GRACE score (P < 0.001) for identifying patients with significant CAD. Impaired values of 2D-STE LV GLS were significantly associated with the presence of CAD in hsTnI-negative UA patients and demonstrated better discriminative power than LVEF and the GRACE score.