ENThe present paper deals with the process of changes of Lithuanian folk fiddle music during the last century. The studying of Lithuanian folk fiddle repertoire and music stylistics is still at its initial stage. Therefore quite a restricted object was chosen - fiddle music played by Lithuanian folk musician Stanislovas Baltrušaitis (1898-1993) and his son Feliksas Baltrušaitis (born in 1929). Both of fiddlers excellently represent traditions of their native land (Šiauliai region, Raudėnai rural district; northwestern Lithuania) which is one of the most distinct centres of the folk fiddle music making. They played several times for audio and video recordings and have been quite comprehensively questioned by ethnomusicologists. An attempt has been made to study and compare the repertoire and playing style peculiarities of S. and F. Baltrušaitis. The aim of this investigation is to reveal what genres and peculiarities of fiddle music have remained and, on the other hand, how it has changed regarding its functions and social-cultural situation. The investigation performed enabled us draw a conclusion that during the previous century, and especially in its second half, Lithuanian folk fiddle music underwent noticeable changes, though it has preserved some older traditional peculiarities. The large repertoire of Stanislovas Baltrušaitis (71 pieces with only some tunes of the same invariant have been recorded) consists mainly of polkas (35) and traditional two and more part dances (25). Polkas composed by him (9) are very close to the tradition, except one, under the title "Without any sense". Feliksas Baltrušaitis has learned a big part of his fiddle repertoire (49 pieces recorded) from the father, but he can play substantially less traditional dances (9) and even polkas (19), he does not remember country-dances as well as certain ritual dances and marches at all.He plays much more foxtrots, songs similar to the romances and other popular pieces of his youth time, which are still not all recorded yet. Since 1963 F. Baltrušaitis, "seeking to keep his father's music known", has been co-operating with the famous Lithuanian professional violinist and composer Jurgis Gaižauskas who has composed, beside other genres, a lot of instrumental pieces for the transformed "country-side bands". Influenced by the performing in these bands F. Baltrušaitis can play quite a lot of pieces in two versions, both learned by ear: "as in former times" and "how J. Gaižauskas has created", i.e. unified versions spread all over Lithuania. Both the Baltrušaitis are brilliant and inventive improvisers. S. Baltrušaitis obtains quite an intensive sound, sometimes with powerful accents as it belongs to the dance music having to involve and organise the dancers. His music has distinguishing traits of the older instrumental style: often occurring free as well as asymmetrical melody, irregular tempo and metro-rhythmic, fanfare melodic in triplet rhythm, a common ending for many pieces, etc. F. Baltrušaitis' style presents quite a few explicit differences: a very light sound, oft-occurring dynamic effects and vibration. His characteristic melodic embellishments are groups of fourfive notes (not the trills as of his father) and longer passages. Playing polkas created by him F. Baltrušaitis has a goal to stun the audience with his technical perfection. He uses the changes of tempo for the sake of greater artistry. All these differences could be explained not only as peculiarities of his individual style, but also as an outcome of the influence of stage show performances with a prevailing aesthetic function. [From the publication]