C-type natriuretic peptide (CNP) significantly increases in chronic heart failure (CHF) patients as a function of clinical severity. Aim of this study was to evaluate in CHF patients the relationship between circulating CNP concentrations and echo-Doppler conventional indices of left ventricular (LV) function as well as less load independent parameters as d P/d t. LV ejection fraction (EF), left ventricular end-diastolic dimension (LVEDD) and LV d P/d t were evaluated together with plasma CNP levels in 38 patients with CHF and in 63 controls. CNP levels resulted significantly higher in CHF patients than in controls (7.19 ± 0.59 pg/ml vs. 2.52 ± 0.12 pg/ml, p < 0.0001). A significant correlation between d P/d t and CNP levels ( r = −0.61, p < 0.0001) was observed. A good correlation with EF ( r = −0.55, p < 0.001) and a less significant relation with LVEDD ( r = 0.316, p < 0.05) were also reported. When patients were divided according to d P/d t values a very significant difference in CNP levels was observed: Group I (<600, n = 25) vs. Group II (>600, n = 13): 8.46 ± 0.69 and 4.75 ± 0.75 pg/ml, respectively, p < 0.001. This is the first study that reports a correlation between CNP and d P/d t in CHF patients, thus suggesting a possible role on cardiac contractility.