To investigate the relationship between the HALP score (haemoglobin, albumin, lymphocyte, and platelet), the modified HALP (m-HALP) score, and prognosis in patients presenting to the emergency department (ED) with acute heart failure (AHF). A Descriptive study. The Emergency Department of Balikesir University Hospital, Turkey, between January 2019 and September 2021. Patients diagnosed with AHF were divided into two groups, namely survivors and non-survivors. Both groups were compared in terms of HALP, m-HALP, PLT, NLR and PLR values ROC curve analysis was performed to evaluate their diagnostic performances in discriminating between one-week and three-month mortality. Youden J index was used to obtain the optimal cut-off value. The mean age of 101 patients included in the study was 73.15±10.19 years, with 51.5% (n=52) females, and 48.5% (n=49) males. The 1-week and 3-month mortality rates were 11.9% and 38.6%, respectively. For 1-week (p=0.018) and 3-month (p=0.006) mortality, platelet was significantly higher in the survivor group than in the non-survivor group. The m-HALP score and the NLR were found to be good predictors for 3-month mortality (p=0.002 and 0.016 respectively). The optimal cut-off values of m-HALP score, the platelet, and the NLR in predicting 3-month mortality were found as ≤1081723.5, ≤217, and >8.4. The area under curve (AUC) values were found as 0.687, 0.663, and 0.643, respectively. The sensitivity of the m-HALP score, the platelet, and the NLR were 76.92, 66.67, and 46.15, and the specificity values were 56.45, 67.74, and 79.03, respectively. The m-HALP score was found to be a potential independent prognostic index for patients with AHF. The classical HALP score was not adequate to predict early and late prognosis. In addition, thrombocytopenia and increased NLR were associated with increased mortality in patients with AHF. Acute heart failure (AHF), HALP score, m-HALP score, Neutrophil lymphocyte ratio (NLR), Platelet lymphocyte ratio (PLR), Platelet (PLT).