The objective of this study was to evaluate three decision-support tools (the Pre-Arrest Morbidity or PAM score, the Prognosis After Resuscitation or PAR score, and the Acute Physiology and Chronic Health Evaluation or APACHE III score) for their abilities to predict the outcomes of in-hospital cardiopulmonary resuscitation (CPR). The medical records of all 656 adult inpatients undergoing CPR during a two-to-three-year period in three large hospitals were retrospectively reviewed, and demographic and clinical variables were abstracted. Of 656 patients undergoing resuscitation, 248 (37.8%) survived the resuscitation attempt long enough to be stabilized (immediate survival), but only 35 (5.3%) survived to discharge. Only 11 patients had PAM scores higher than 8, none of whom survived to discharge; 131 patients had PAR scores above 8, of whom six survived to discharge. The PAR score and the APACHE III score had the greatest areas under the receiver operating characteristic curves (when predicting the outcome of survival to discharge), although no individual area for either outcome was greater than 0.6. None of the decision-support tools studied was able to effectively discriminate between survivors and non-survivors for the outcomes of immediate survival and survival to discharge following in-hospital CPR. This is consistent with previous work utilizing the APACHE II score, which did not identify a threshold above which patients did not benefit from CPR. The findings for the PAR score and the PAM score stand in contrast to previous studies that found them to be potentially useful decision rules. Further work is needed to develop a decision-support tool that better discriminates between survivors and non-survivors of in-hospital CPR.