Background: Anthracycline (A) and trastuzumab (T) chemotherapy have well-recognized cardiac toxicity, potentially leading to significant morbidity and mortality. Our previous work in 46 prospectively enrolled breast cancer patients showed early left ventricular (LV) and right ventricular (RV) function decline at 1 and 3 months, but only persistent RV dysfunction at 12 months which correlated with myocardial oedema observed early (1 and 3 months) after administration of chemotherapy regimes. Method: To investigate late cardiac effects, the same cohort were re-imaged with advanced Cardiovascular Magnetic Resonance (CMR) imaging including T1 mapping 5 ± 1 year post chemotherapy. Results: Twenty-six out of 46 (50%) patients underwent follow-up imaging. A statistical but non-clinically significant decrease was observed in LV ejection fraction (EF) from baseline to 5 years (72.2 ± 6.6 to 65.4 ± 9.3, p < 0.005). Subjects with initial drop of LVEF by >10% at 3 months (n = 5) or at 12 months (n = 3) did not demonstrate any difference in LV or RVEF at 5 years. No correlation was observed between myocardial oedema and LV or RVEF at 5 years. At 5 years, T1 values were within normal limits overall (935 ± 48 ms). One patients had significantly elevated (>1000 ms) T1 values with no correlation to LV or RVEF. No subjects demonstrated replacement myocardial fibrosis at 5 years. Conclusion: Using advanced CMR, contemporary chemotherapy regimes demonstrate minimal long-term cardiac toxicity. There is minimal diffuse and no replacement fibrosis as demonstrated by LGE, following chemotherapy. This study suggests limiting serial imaging in these patients at 12 months post chemotherapy.