Wireless LANs not only provide an affective means of communication, but also allow to extract information about the location of mobile stations. Numerous wireless LAN location systems have been proposed in the past, yet it is difficult to compare the performance of different systems, since the conditions under which these systems are evaluated differ considerably. Hence, the accuracy information presented in literature varies widely, even for conceptually identical systems. This paper proposes to evaluate the performance of location systems in standardised test environments. To this end, existing location systems are discussed to assess their information requirements and their reported accuracies. Subsequently, the requirements for benchmarks in the context of Wireless LAN location systems are established. To conclude, a publicly available benchmark is presented against which different Wireless LAN location systems can be compared