The text discusses words occurring in the Polish-East Slavic borderlands and prevalent in eastern Polish dialects. Differntiation between old references and loans in this area is not always easy. The material presented here is very diverse. In the case of certain words, identifying them as East Slavic loans with an indisputable source is possible, while in the case of others it is difficult to identify the direct source of the loan. Among the words recorded in the East Slavic borderlands we can find those whose range in Polish dialects seems to indicate the possibility of Ruthenian influence; however, their Polish phonetic form implies their native origin and one should speak about an old reference in this respect. We also encounter Pan-Slavic words, where a doubt arises as to whether they are loans or old references in Polish in the East Slavic area and Eastern Poland.