The paper presents a couple of findings of a study in wireless LAN security (WLAN) in German companies and federal authorities. The study was conducted in spring 2009. On the basis of a directory of security measures we formulate hypotheses derived from several studies in WLAN security. We analyze how the situation in Germany fits these assumptions. Degree of familiarity, frequency of use and reasons for not using wireless LAN security measures are being investigated. Furthermore, we discuss correlations between companies’ characteristics and the use of security measures.