Background: We aimed to evaluate whether baseline GLS and NT-proBNP and their changes after cardiac resynchronization therapy (CRT) can predict the long-term clinical outcomes and the echocardiographic-based response to CRT (defined by 15% relative reduction in left ventricular end-systolic volume). Methods: We enrolled 143 patients with stable, ischemic heart failure (HF) undergoing CRT-D implantation. NT-proBNP and echocardiogram were obtained before and 6 months after. The patients were followed-up (median: 58 months) for HF-related deaths and/or HF hospitalizations (primary endpoint) or HF-related deaths (secondary endpoint) Results: 84 patients achieved the primary and 53 the secondary endpoint, while 104 patients were considered as CRT-responders and 39 as non-responders. At baseline, event-free patients had higher absolute GLS values (p<0.001) and lower NT-proBNP serum levels (p<0001) than those achieving primary endpoint. A similar pattern was observed in favor of CRT-responders vs non-responders. In Cox regression analysis, lower baseline absolute GLS value (HR=0.77;95%CI, 0.51-1.91; p=0.002), higher baseline NT-proBNP levels (HR=1.55;95%CI, 1.43-2.01;p=0.002) and diabetes (HR=1.27;95%CI, 1.12-1.98;p=0.003) were associated with lower incidence of primary endpoint. Conclusions: In HF patients undergoing CRT-D, baseline GLS and NT-proBNP concentrations may serve as prognostic factors, while they may predict the echocardiographic-based response to CRT.