The aim of this study was to explore the epidemiologic characteristics of unintentional poisoning cases and the factors associated with inpatient mortality. Data were retrieved from the National Health Insurance database from 2005 to 2007. Patients with diagnosis classifications of ICD-9-CM E850-E869 (unintentional poisoning) were selected. SPSS 18.0 software was used for the analysis. In Taiwan between 2005 and 2007, a total of 11,523 patients were hospitalised due to unintentional poisoning, with a hospitalisation rate of 16.83 per 100,000, of which 60.1% and 39.9% were attributable to drug poisoning and solid, liquid and gas substance poisoning, respectively. The hospitalisation rate in men was higher than that of women. The age group of 45-64 had the highest hospitalisation rate of 52.85 per 100,000. The inpatient mortality rate increased with the presence of the following factors: age of 65 or older, surgery or procedure, a higher Charlson Comorbidity Index (CCI), short length of hospital stays, acute respiratory failure, alcohol poisoning, pesticide poisoning and a higher-level hospital visited. Methanol, herbicides and organophosphorus pesticide intoxications are associated with higher mortality rates. Therefore, when caring for patients poisoned by the above agents, healthcare professionals should look out for their clinical development to ensure quality of care and to reduce mortality.