Objectives: To know the rate of nosocomial infections in open prostate surgery and to assess the application of pre-surgery preparation and preoperative antibiotic prophylaxis protocols at three public hospitals in the Autonomous Community of Madrid. Materials and methods: Prospective observational and multicentre study, including all the patients operated on at the services monitored and admitted for more than 48 hours between 1 January and 31 December 2009. They were monitored from admittance until their discharge. Results: The rate of hospital infection observed was 3.38%. The most frequent infection was surgical localization, with an incidence rate of 2.77% (superficial = 1.23%; deep = 0.31%; organspace = 1.23%). The percentage of appropriate surgical prophylaxis, both in the indication and in the selection of antibiotics, initiation and duration, with respect to all those patients that received it, was 47.42%. According to the data obtained from their clinical records, the percentage of patients in which the pre-surgery preparation protocol was correctly complied with, was 92%. Conclusions: The results obtained in this multicentre study can serve not only as a reference to other public hospitals, but they are also comparable to other international monitoring systems. Monitoring and controlling infections associated with healthcare must be a key aspect in Patient Care and Safety programmes.