Experiments conducted over the last few years with the SMART document retrieval system have shown that fully automatic text processing methods using relatively simple English language analysis tools are as effective for document indexing, classification, search, and retrieval as the more elaborate manual methods normally used. The present study describes an extension of the SMART procedures to German language materials. A multilingual thesaurus is used for the analysis of documents and search requests, and tools are provided which make it possible to process English documents against German queries, and vice versa. The methods are evaluated and it is shown that the effectiveness of the mixed language processing is approximately equivalent to that of the standard process operating within a single language only.