The objectives of this study were to characterize peri-operative echocardiographic (ECHO) assessments of right ventricular (RV) function and pulmonary hypertension (PH) and ascertain correlation with clinical outcomes in infants with left Bochdalek’s hernia (LBH). This retrospective study in a quaternary neonatal intensive care unit involved electronic database search for infants with LBH during January 2009 to July 2017. Demographics, outcomes, and ECHO parameters were accessed from archived databases. Thirty-one infants with mean gestational age and birthweight (BW) 38.4 ± 1.4 weeks and 3079 ± 450 g were included. Postnatal age at surgery was 4.3 ± 2 days. Two infants died before surgery (none after surgery). The survival rate in this cohort of late preterm and term infants with LBH not accompanied by congenital heart disease was 29/31 (93.5%). PH was noted in 28 (90%). Significant changes in biventricular function and pulmonary vascular haemodynamics were noted when reassessed after surgery [RV area change (%), 28 ± 3 vs. 34 ± 4, p = 0.007 and pulmonary artery capacitance (PAC) (ml³ × mmHg⁻¹), 0.05 ± 0.03 vs. 0.09 ± 0.05, p = 0.02]. The median duration of all respiratory support in those who were operated was 14.7 days (8.5, 25). Significant correlations were noted between pre-operative ECHO assessments and the duration of respiratory support (tricuspid regurgitation, r = 0.63, p = 0.0001 and PAC, r = − 0.52, p = 0.004). Peri-operative functional ECHO provided information about the evolution of cardiac function in infants with LBH.