Background: An increase in intraabdominal pressure (IAP) during acute heart failure, seems to be directly related to worsening renal function, which leads to worse clinical outcomes. We aimed to analyze the relationship between IAP and determinants of renal function during admission for acute decompensation of heart failure (ADHF) in a conventional Internal Medicine Ward., Patients and Methods: Descriptive and prospective study. Patients admitted for ADHF with an estimated glomerular filtration rate > 30mL/min/1.73 m 2 , willing to participate and who gave their informed consent were included. Ethics Committee of Aragon approved the protocol (PI 15 0227)., Results: We hereby report the results of an interim analysis of the first 28 patients included. Patients were divided in 2groups according to the median of IAP measured during the first 24h after admission for ADHF, namely high IAP (IAP>15mmHg) and low (IAP< 15mmHg). Fourteen patients were included in each group. No differences were found in baseline clinical characteristics, comorbidities or treatment between both groups. Patients with IAP above 15mmHg, showed a significant lower baseline estimated glomerular filtration rate (70.7 vs. 44.4mL/min/1.73 m 2 with p=0.004], blood urea 36 vs. 83mg/dL with p=0.002]; serum creatinine 0.87 vs. 1.3mg/dL with p=0.004 and cystatin C 1.2 vs. 1.94mg/dL with p= 0.002. Additionally, these patients had higher uric acid (5.7 vs. 8.0, p=0.046), lower hemoglobin concentrations (11.7 vs. 10.5g/L, p=0.04) and longer length of hospital stay (6.5 vs. 9.6 days, p=0.017)., Conclusions: The increase in IAP seems to be a frequent finding in patients admitted for ADHF. Patients share similar clinical profile irrespective of IAP, although the increase in IAP is associated with a significant baseline impairment of renal function., (Copyright © 2018 Elsevier España, S.L.U. and Sociedad Española de Medicina Interna (SEMI). All rights reserved.)