The aim of this thesis was to evaluate the music downloading service Musikwebb regarding its indexing and retrieval effectiveness. This was done by performing various kinds of search in the system. The outcome of these searches were then analysed according to the criteria specificity, precision, recall, exclusivity and authority control. The study showed that Musikwebb had several flaws regarding its retrieval effectiveness. The most prominent cases were the criteria exclusivity and specificity. Several of Musikwebb’s classes could be regarded as almost similar and the average number of songs in each class was over 50 000. As this study shows, having over 50 000 unique entries in a class results in problems regarding the effectiveness of the browsing technique. The developers of Musikwebb are recommended by the author to acquire their licensed material from All Music Guide, including the implementation of the All Music Guide classification system.