Imre Waldbauer (1892–1952) attained his greatest stature as a performer in his position as the first violinist of the Waldbauer–Kerpely Quartet, named after him and cellist Jenő Kerpely. This ensemble premièred Bartók's String Quartets nos. 1, 2 and 4 and his early Piano Quintet. Although Waldbauer's name is mostly mentioned in the Bartók-literature primarily because of his quartet, he was also important for Bartók as a “standalone” violinist as well. Waldbauer and Bartók played numerous sonata recitals from the 1910s to the 1930s, and Waldbauer also played the first performance of important violin works by Bartók: the “One Ideal” from the Two Portraits, (première: Budapest, 12 February 1911), the Violin Sonata no. 2 (première: Berlin, 7 February 1923) and nos. 16, 19, 21, 28, 36, 42, 43, 44 from the Forty-Four Duos (concert hall première: Budapest, 20 January 1932). Although Waldbauer seems like an individual of special importance, very little is known about his relation to Bartók and about his life in general (unlike his violinist contemporaries, e.g. Joseph Szigeti or Zoltán Székely). The present paper focuses on the relationship between the composer and the violinist, using materials from the yet unexplored Waldbauer legacy held in the Budapest Bartók Archives (recent donation from the Waldbauer family).