We investigated whether acute and chronic administration of zofenopril, an angiotensin converting enzyme inhibitor, may modulate the expression of genes which are involved in the pathophysiology of myocardial ischemia and heart failure. We used an acute and a chronic model. In the former isolated rat hearts were perfused for 120 min in the presence or in the absence of 10 μM zofenoprilat, the active metabolite of zofenopril. In the chronic model one group of rats was treated with zofenopril (15.2 mg/Kg die per os) for 15 days, while control rats were treated with the same diet, except that zofenopril was omitted. Total RNA was extracted from hearts, and quantitative reverse transcription-polymerase chain reaction (qRT-PCR) was used to evaluate the expression of α myosin heavy chain, superoxide dismutase, heat shock protein 70 (HSP70), nitric oxide synthase 2 and 3 (NOS2, NOS3), heme oxygenase 1, atrial natriuretic peptide (ANP), muscle phosphofructokinase. Acute or chronic zofenopril administration did not produce any change in hemodynamic variables. qRT-PCR experiments showed that in the acute model ANP expression was slightly although not significantly increased. In the chronic model, significant changes in gene expression were detected: in particular, HSP70 was upregulated (1.06 ± 0.38 vs. 0.72 ± 0.20 arbitrary units, P = 0.025), while NOS3 was downregulated (0.66 ± 0.06 vs. 0.83 ± 0.18 arbitrary units, P = 0.007). In the chronic model, liver samples were also assayed, but no significant change in the expression of any gene was detected. We conclude that zofenopril can produce heart-specific effects on gene expression. Persistent changes were detected with regard to specific heat shock protein and nitric oxide synthase subtypes. This action might contribute to the therapeutical response, and particularly to the increased resistance to ischemia.