A telemedicine network has been established in Brazil to support distance medical practice in paediatric oncology. ONCONET comprises a national network of universities, research institutes and medical institutions. The system is Web-based and hosted on a high-performance computing infrastructure based on clusters of computers. It is based on open-source software, designed to provide high performance, fault tolerance and high availability. The ONCONET began operation in 2004. Currently, 30 hospitals affiliated to the Brazilian Society for Paediatric Oncology are users of the ONCONET. Six hospitals are connected by broadband access through the National Education and Research Network and 24 by conventional Internet access. The Multimedia Patients Registry also became operational in 2004, and its database contains information on 3,200 patients from the 30 hospitals. The technological platform was notable for its low production cost. It thus appears to be a sustainable solution to the problem of delivering continuing medical education in a large country with widely dispersed health professionals.