Background: Recently, procalcitonin (PCT) has been identified as a useful biomarker to identify heart failure with bacterial pneumonia in clinical trials. Objective: This study aimedto assess the role of procalcitonin in diagnosis of bacterial pneumonia in patients with congestive heart failure. Patients and methods: The study was conducted in Chest Department, Cardiology Department and Cardiology Outpatient Clinic, Zagazig University Hospitals as a case control study. This study included sixty participants who were classified into 3 groups. Group 1 included 20 chronic stable heart failure patients, Group 2 comprised 20 diagnosed bacterial community-acquired pneumonia on top of chronic heart failure patients. Group 3 consisted of 20 healthy individuals as control group. All participants were subjected to full medical history, clinical examination, chest radiography, CT scan of the chest, ECG, echocardiography, microbiological investigations, general investigations (TLC, ESR, CRP, electrolytes, LFT, KFT, random and fasting blood sugar levels) and specific laboratory investigations (serum PCT level). Results: Procalcitonin levels differed significantly among the groups studied. There was a substantial difference between the groups when comparing them pairwise. The best cut-off of PCT in diagnosis of bacterial pneumonia in CHF patients was ≥ 0.555 ng/ml with area under curve of 0.994, sensitivity of 95%, specificity of 97.5%, positive predictive value (PPV) of 95%, negative predictive value of 97.5% and accuracy of 96.7% (p < 0.001). Conclusion: Procalcitonin measurement is useful in differentiating bacterial pneumonia in patients with heart failure from heart failure patients without pneumonia, hoping for better patient care.