Purpose: The aim of this study was to investigate whether laboratory findings on arrival may be useful in predicting the outcome of out-of-hospital cardiopulmonary arrest (CPA). Methods: Between January 2005 and September 2007, a medical chart review was retrospectively performed for CPA. The individual medical records were reviewed for the following data: background of CPA, arterial blood gas, cell blood count, serum biochemical, and cerebral performance category (CPC) 1 month after the CPA. The subjects were divided into patients with a CPC ranging from 3 to 5 (CPC 3-5 group) and from 1 to 2 (CPC 1-2 group). Findings: The total protein, platelets, pH, and Po(2) in the CPC 1-2 group tended be higher than those in the CPC 3-5 group. The P(co2), potassium, phosphorus, and ammonia in the CPC 1-2 group tended be lower than those in the CPC 3-5 group. However, there were no factors independently associated with the outcome by multivariate analysis. Conclusion: Some of the biochemical-hematologic parameters demonstrate significant changes concerning the outcome. However, initial blood work cannot be used to make clinical decisions because there are no factors independently associated with the outcome. (C) 2009 Published by Elsevier Inc.