ENThe article discusses the surnames of the Lithuanian-speaking residents of Seinai region. The names were undoubtedly formed on the basis of the Lithuanian language, and only in exceptional cases one can come across the names borrowed from foreign languages. The author tried to provide the greatest possible number of personal names. Yet, due to the fact that he did not have access to the census data, he had difficulties in collecting the full list. Local residential Phonebooks from the Punskas, Seinai and Suvalkai areas as well as the city of Białystok served as his source material. The author also referred to his own memory to fill in the gaps for certain surnames. Names are an interesting object of study from the perspective of linguistics. Lithuanian names are very old, yet surnames developed relatively recently in our region. Most of them were only established in the 17th and 18th centuries. Only surnames derived from either the ancient and now unused names or the nicknames are much older. The construction of the term 'surname' itself shows that it is a newer or a secondary 'product'. Accordingly, a word 'pavardė' itself (surname) in Lithuanian indicates that it goes after the name. The 'newer' character of surnames makes it easier to understand their origin. People are named just after birth, the surnames, however, are inherited from the male line of the family. Customarily surnames were derived from the characteristics attributed to a particular person - be it the father's name, occupations performed, places of residence, or some other characteristic features.Thus, to a large degree, surnames allow one to determine a social status of the ancestors. When surnames were forming, Lithuania was not a sovereign country. Moreover, there was a lack of national official language. Lithuanian names have had various distortions as a result of different dominant administration languages in Lithuania throughout history. First there were Old Church Slavonic and Latin languages, followed by Polish after the Union of Lublin and German, especially in the territory of Lithuania Minor (the Karaliaučius area) and Klaipėda, and finally Russian as a result of the annexation of the state. Close contact with other languages created the jargon in the Lithuanian language, which also found some reflection in the word formation, including surnames. Official surname forms currently used in Poland have also lost etymological transparency due to the officials' inability to write them correctly. Only the forms preserved in spoken Lithuanian are closest to their roots and allow us to determine their origin. The author encourages the readers to take interest in surnames and the past of our ancestors written in them.