Abstract Introduction The presence of left bundle branch block (LBBB), although extensively studied, is still associated with many gaps in the knowledge of the underlying associated diseases. Although LBBB can sometimes be found in asymptomatic individuals with structurally normal heart, majority of patients with LBBB have some form of underlying heart disease, including coronary artery disease (CAD). Myocardial perfusion scintigraphy with pharmacological stress testing is one of the recommended non-invasive tests in patients with LBBB and suspected CAD. Heart failure, progressive conductive system disease and other cardiomyopathies can be also associated with LBBB. Purpose of our study was to assess the clinical characteristics and results of myocardial perfusion scintigraphy on patients with LBBB. Methods The clinical data and myocardial perfusion scintigraphy results of 5168 consecutive patients admitted to our department from January 2020 to December 2023 were prospectively collected. All patients underwent a 2-day stress/rest 99mTc tetrofosmin (Myoview, GE Healthcare) MPI. Patients were imaged in the sitting position using a Cardius® X-ACT camera (Digirad, California, USA). Patients were categorized into LBBB and without LBBB groups. Results 284 patients (5.5%) had LBBB. Clinical characteristics of the patients with and without LBBB are shown in Table 1. Patients in LBBB group were older and predominantly female. There were no differences in the prevalence of cardiovascular risk factors between the groups. The proportion of patients with reversible ischaemia was lower in patients with LBBB (Table 1). The extent of ischaemia was similar in both groups (Table 2). The summed stress score (on scintigrams with and without attenuation correction) was higher in patients with LBBB, due to expected perfusion artefacts (Table 2). Conclusions The findings of our study indicated that the presence of LBBB is associated with a lower incidence of reversible ischaemia on myocardial perfusion scintigraphy than in the non-LBBB population. This suggests that the impact of CAD as the leading underlying cause of LBBB could be less significant, possibly due to modern diagnostic and treatment options. Consequently, other factors might have more influence. Supporting this notion, the data reveals that patients with LBBB were typically older and exhibited a higher prevalence of heart failure.