Heart disease is the leading cause of non-cancer death in childhood cancer survivors. to determine the prevalence of subclinical cardiac dysfunction using speckle tracking and compare its results with those obtained by classical methods of assessing left ventricular function and its relationship with different factors to identify the population at higher risk. Echocardiographic assessment of left ventricular function included ejection fraction, tissue Doppler, longitudinal/circumferential strains and biochemical parameters (troponin-T and Pro-BNP) in a cohort of 57 survivors of childhood acute leukaemia with at least 10 years since diagnosis. Ventricular dysfunction was found in 5.2% of patients in M-mode (ejection fraction—EF < 53% with a reduction in the EF ≥ 10%) and in 7% of patients with Simpson’s method, compared with 21.05 and 8.8% with suboptimal global longitudinal strain (GLS) and global circumferential strain, respectively. The GLS alteration was significantly correlated with lower values of left ventricular systolic function and was associated with high tumour risk (odds ratio [OR] 13.8), cumulative doses of anthracyclines ≥ 250 mg/m² (OR 7.6) and radiotherapy (OR 7.19). Biomarkers were not useful for the diagnosis of subclinical cardiomyopathy. Good reproducibility was obtained, with an intraobserver correlation of 93.6% and an interobserver correlation of 89.2% in the GLS. The alteration of the GLS was more prevalent than the alteration in the EF and was associated with the treatment received and high tumour risk. strain imaging seems to be a powerful tool to identify an increased number of survivor with an early myocardial injury.