Abstract. With the integration of security-critical services into Building Automation Systems (BAS), the demands on the underlying network technologies increase rapidly. Relying on physically isolated networks and on “Security by Obscurity”, as it is still common today, is by no means an adequate solution. To be reliable and robust against malicious manipulations, the used communication services must support advanced security mechanisms that counteract potential security threats. This paper identifies important security requirements and challenges within the building automation domain. Based on this analysis, state-of-the-art technologies are carefully examined. Finally, an outlook on advanced security concepts is given. Key words: Building Automation, Embedded Networks, Security