An exploratory study of factors leading to preventable hospital admissions focusing on a medical ward population found a large proportion of patients with preventable illnesses or illnesses sufficiently modifiable to have made admission avoidable. This report presents methods for assessing preventability and some preliminary findings relative to patient and physician failures. Leading patient failures included heavy cigarette smoking, obesity, delay, drug abuse, and alcohol problems. Physician failures included both diagnostic and treatment errors. While patient failures were more numerous, physician failures seemed more consequential with reference to preventing hospital admissions.