Background Sacubitril/Valsartan has been shown to improve mortality and reduce hospitalizations in patients with heart failure with reduced ejection fraction (HFrEF). Moreover Sacubitril/Valsartan showed a significantly reduction in the HbA1c in diabetic patients. The effect of Sacubitril/Valsartan on metabolic parameter and insulin resistence in both, non obese and non diabetic patients, have not been previously described. Aim We evaluated the effects of the Sacubitril/Valsartan on both glycaemic and metabolic parameter, on HOMA–IR and on echocardiographic parameters in patients with HFrEF. Methods A total of 59 non obese and non diabetic patients with a diagnosis of HFrEF (EF Results Data analysis demostrated a significant reduction in fasting plasma glucose (111.4 + 11.5 vs 106 + 10 mg/dl, P = 0.03), fasting plasma insulin (13.6 + 5.9 vs 10.5 + 4.4 µUI/ml), HbA1c value (6.14 + 0.5% vs 5.9 + 0.3%, P Conclusions Our data, even if preliminary, seem to indicate that sacubitril/valsartan might enhance glycaemic control and improve insulin resistance in non obese/non diabetic patients with HFrEF. Also, our data confirm that sacubitril/valsartan treatment is able to improve ejection fraction in HFrEF patients.