['Multidimensional impairment of older patients may influence the clinical outcome of diseases. The aim of this study was to evaluate whether a Multidimensional Prognostic Index (MPI) based on a comprehensive geriatric assessment predicts short-term mortality in older patients with heart failure.', 'In this prospective study with a 1-month follow-up, 376 patients aged 65 and older with a diagnosis of heart failure were enrolled. A standardized comprehensive geriatric assessment that included information on functional (activities of daily living and instrumental activities of daily living), cognitive (Short Portable Mental Status Questionnaire), and nutritional status (Mini Nutritional Assessment), as well as on risk of pressure sore (Exton-Smith Scale), comorbidities (Cumulative Illness Rating Scale Index), medications, and social support network, was used to calculate the MPI for mortality using a previously validated algorithm. The New York Heart Association, the Enhanced Feedback for Effective Cardiac Treatment, and the Acute Decompensated Heart Failure National Registry regression model scores were also calculated. Higher MPI values were significantly associated with higher 30-day mortality, both in men (MPI-1, 2.8%; MPI-2, 15.3%; MPI-3, 47.4%; P=0.000) and women (MPI-1, 0%; MPI-2, 6.5%; MPI-3, 14.6%; P=0.011). The discrimination of the MPI was also good, with areas under the receiver operating characteristic curves (men: 0.83; 95% CI, 0.75 to 0.90; women: 0.80; 95% CI, 0.71 to 0.89) greater than receiver operating characteristic areas of New York Heart Association (men: 0.63; 95% CI, 0.57 to 0.69; P=0.015; women: 0.65; 95% CI, 0.55 to 0.75; P=0.064), Enhanced Feedback for Effective Cardiac Treatment (men: 0.69; 95% CI, 0.58 to 0.79; P=0.045; women: 0.71; 95% CI, 0.55 to 0.87; P=0.443), and Acute Decompensated Heart Failure National Registry scores (men: 0.65; 95% CI, 0.52 to 0.78; P=0.023; women: 0.67; 95% CI, 0.49 to 0.83, P=0.171).'] Does multidimensional Prognostic Index based on a comprehensive geriatric assessment predict short-term mortality in older patients with heart failure?