The majority of patients hospitalized for heart failure (HF) are admitted to internal medicine (IM) rather than to cardiology (CA) units, but to date few studies have analyzed the characteristics of these two populations. In this snapshot survey, we compared consecutive patients admitted for HF in six IM units vs. one non-intensive CA unit. During the 6-month survey period, 467 patients were enrolled (127 in CA, 27.2% vs. 340 in IM, 72.8%). IM patients were almost 10 years older (CA 75 ± 10, IM 82 ± 8 years; p < 0.001), more frequently female (CA 39%, IM 55%; p = 0.002) and living at home alone (CA 12%, IM 21%; p = 0.017). The leading cause of hospitalization in both groups was acute worsening of HF (CA 42%, IM 53%; p = 0.031), followed by atrial fibrillation (CA 29%, IM 12%; p < 0.001) and infections (CA 24%, IM 27%; p = 0.563). Ischemic (CA 43%, IM 30%; p = 0.008) and dilated cardiomyopathy patients (CA 21%, IM 12%; p < 0.001) were primarily admitted to CA unit, whereas those with hypertensive heart disease to IM (CA 3%, IM 39%; p < 0.001). Left ventricular ejection fraction (LVEF) was available in 96% of CA patients, but only in 60% of IM patients (p = 0.001). Among patients with LVEF measured, those with LVEF < 40% were predominantly admitted to CA (CA 60%, IM 14%; p < 0.001), whereas those with LVEF ≥ 50% were admitted to IM (CA 21%, IM 33%; p = 0.019); 26% of IM patients were discharged without a known LVEF. Medical treatments also significantly differed, according to patients' clinical and instrumental characteristics in each unit. This study demonstrates important differences between HF patients hospitalized in CA vs. IM, and the need for a greater interaction between these two medical specialties for a better care of HF patients.