Abstract. In this paper, we present a framework for managing heterogeneous, multimodal digitized music collections containing visual music representations (scanned sheet music) as well as acoustic music material (audio recordings). As a first contribution, we propose a preprocessing workflow comprising feature extraction, audio indexing, and music synchronization (linking the visual with the acoustic data). Then, as a second contribution, we introduce novel user interfaces for multimodal music presentation, navigation, and content-based retrieval. In particular, our system offers high quality audio playback with time-synchronous display of the digitized sheet music. Furthermore, our system allows a user to select regions within the scanned pages of a musical score in order to search for musically similar sections within the audio documents. Our novel user interfaces and search functionalities will be integrated into the library service system of the Bavarian State Library as part of th...