This study analyzed the writing failure of the computerized physician order entry system and its advantages and disadvantages according to users. At a university hospital 1,351 physician orders were analyzed and 84 nursing and medical professionals were interviewed. The results showed that 17.7% of the orders presented erasures, medication had been suspended in 16.8%, in 28.2% there was dubious or misleading information and in 25% medication had been prescribed manually. The professionals indicated advantages such as: ease of data reading and the quickness with which the order is entered and released, among others. They also reported disadvantages such as the repetition of orders from previous days without a review and incorrectly typed information. Therefore, it is concluded that, despite representing an important strategy for error reduction, this system must be overhauled and professionals must be trained to use it.