We describe WebCLEF, the multilingual web track, that was introduced at CLEF 2005. We provide details of the tasks, the topics, and the results of WebCLEF participants. The mixed monolingual task proved an interesting addition to the range of tasks in cross-language information retrieval. Although it may be too early to talk about a solved problem, effective web retrieval techniques seem to carry over to this particular multilingual setting. The multilingual task, in contrast, is still very far from being a solved problem. Remarkably, using non-translated English queries proved more successful than using translations of the English queries. Categories and Subject Descriptors H.3 [Information Storage and Retrieval]: H.3.1 Content Analysis and Indexing; H.3.3 Information Search and Retrieval; H.3.4 Systems and Software; H.3.7 Digital Libraries; H.2.3 [Database Management]: Languages—Query Languages General Terms Measurement, Performance, Experimentation Keywords Web retrieval, Known-...