Background Duchenne muscular dystrophy (DMD) is an X-linked hereditary neuromuscular disorder characterized by progressive muscular weakness and the development of a dystrophic cardiomyopathy. Despite standard therapy with ACE-inhibitors (ACEi), betablockers (BB) and mineralocorticoids receptor antagonists (MRA), the progression of left ventricular dysfunction remains one of the main causes of mortality. Sacubitril/valsartan, belonging to the class of angiotensin receptor-neprilysin inhibitor (ARNI), has been shown to be effective in treating heart failure patients with reduced left ventricular ejection fraction; however, data on DMD patients remain limited. Objectives To evaluate the efficacy and the tolerability of sacubitril/valsartan in patients with dystrophic cardiomyopathy. Methods We enrolled 26 consecutive patients affected by DMD with reduced left ventricular ejection fraction (LVEF <40%), on chronic optimal medical therapy, started on sacubitril/valsartan. We evaluated N-terminal pro–B-type natriuretic peptide (NTproBNP), left ventricular ejection fraction (LVEF), renal parameters and pressure levels at baseline and at 3, 6, 12 months and at the last available follow-up. Statistical analysis was conducted with paired-sample t-test or Wilcoxon signed-rank test, with statistical significance set at p < 0.05. Results The median age was 26 ± 4 years; all patients were on chronic therapy with BB and 88% with MRA. LVEF increased from 32.8 ± 3.7% to 35.9 ± 5.5% after 6 months (p = 0.006) and remained stable at 12 months. NTproBNP was reduced from 702 ± 877 to 424 ± 368 pg/ml (p = 0.009). In a single case (3.8%), ARNI was suspended due to worsening renal function; in all other patients renal function remained stable. A mild reduction in blood pressure was observed (from 99.8 ± 10.7 to 93.8 ± 8.1 mmHg, p = 0.02), without therapy discontinuation. Conclusion Sacubitril/valsartan was effective and well tolerated in patients affected by Duchenne dystrophic cardiomyopathy, with improvement of left ventricular function and reduction of neurohormonal cardiac biomarkers, without clinically relevant renal effects. These data support the potential role of sacubitril/valsartan in the management of heart failure in dystrophic cardiomyopathy.