This paper reports on some important findings of a study conducted in Covilhã/ Portugal on appropriateness of hospital admission and in-hospital days in a Portuguese hospital using an adapted version of the Appropriateness Evaluation Protocol – a review tool for hospital utilization. This analysis showed a significant rate of inappropriateness in admission (24, 6%) and days of stay (37, 4%) and it also suggested a low rate of use of the override options. It was possible to identify the conservative attitude as the most common cause of inappropriate admissions and days of stay. This study demonstrates that a high proportion of admissions and days of stay are related to patients who could have been attended at other levels of the health care system such as outpatient consultations. The analysis made it possible to identify and to explore some variables correlated to the levels of inappropriateness and to the causes of inappropriateness or levels of health care required by the patients.