The article is based on previously unpublished archival materials from the Alban Berg Foundation of the Austrian National Library. These are, namely, the composer’s notebooks with his account of the trip to Leningrad to the premiere of the opera Wozzeck in June 1927. The article features facsimiles, transcriptions, and translations of some materials as well as their general description. The jewel of the collection is the notebook that Berg took with him on his trip to Leningrad. It resembles a diary with a detailed account of the trip to Leningrad and back. Inter alia, it describes what Berg did on each of the five days of his stay in Russia and provides a record of cash payments in several currencies. Besides, the new materials reveal that Berg visited a rehearsal and two performances at MALEGOT (now know as the Mikhailovsky Theatre), a performance at the Moscow Art Theater, and one dress rehearsal of Wozzeck. The notebook contains information about the meetings with stage directors N. Smolich and J. Lapitsky, conductor N. Malko, and members of the ASM Leningrad (Association for Contemporary Music). The records also feature numerous addresses of Moscow musicians. The new materials complement the available information on the plans for the production of Wozzeck in other cities and theaters, primarily in the Bolshoi. They also provide a broader context for interpreting the little that is available about Berg’s trip in his letters and interviews. Another notebook, used by Berg on his return from Leningrad, documents the beginning of correspondence with Russian counterparts, much of which is poorly-preserved. It also provides information about translation of Russian reviews through Universal Edition and sheet music sent to Russian musicians. The documents featured in the article shed light and provide important details of Berg’s visit to Leningrad; they contribute to our understanding of relations between Russia and Austria of that time and open up new vistas for archival research.