Aims and background: Data on the prognostic value of N-terminal pro-brain natriuretic peptide (NT-proBNP) for critically ill patients are conflicting. This study aimed to investigate the prognostic value of NT-proBNP in critically ill Indian patients. Materials and methods: This was a retrospective, record-based, observational study conducted in the medicine intensive care unit (ICU) of All India Institute of Medical Sciences, Rishikesh, from December 2023 to May 2024. All patients admitted to the medicine ICU during the study period were eligible for the study. Exclusion criteria included medicolegal cases, age < 18 or >80 years, and patients with missing baseline data. The NT-proBNP was measured on admission. The Mann−Whitney U-test was used to compare ranks, and the receiver operating characteristic curve was used to determine the area under the curve (AUC) and identify the best cut-off values to predict mortality. Results: A total of 137 participants were eligible for the study. The NT-proBNP levels were higher in nonsurvivors compared with survivors, but the difference was not significant (p = 0.121). However, in a subgroup of patients without heart failure and in another subgroup without renal failure, a significant difference was seen in the NT-proBNP values between survivors and nonsurvivors (p = 0.044 and 0.002, respectively). The AUC for predicting mortality was 0.57. Conclusion: The NT-proBNP measured at admission was predictive of in-hospital mortality in nonselective critically ill patients without heart failure and in a subgroup of patients without renal involvement.