In Hungary, the concept of “folk song” was clarified at the beginning of the 20th century only, accordingly, there were no “folk songs” noted down in the 18th century. Still, the number of music sources relating to folk music increased significantly in the 18th century. As a result of their scientific analysis the melodic parallels of some five hundred 18th-century tunes were found in the central folk music collection of the Institute for Musicology of the Hungarian Academy of Sciences. These melodic parallels involve 153 folk song types. In a specific era of folk culture there is always a coexistence of elements and styles of different age. The sources also contain examples of the descending pentatonic styles (that either originates or developed from oriental roots), of the lament style and of the medieval and early modern tunes. Of particular interest are the songs that first appeared in the 17th century, then undergone significant changes in form and rich collection of variants developed around them. The most remarkable result of our research is that contrary to former beliefs regarding its insignificance, the 18th century enriched the Hungarian folk music with some sixty new melody types. One of the most interesting groups of this rather mixed collection of songs is that of the songs in a major key with a narrow compass that seems to be the most characteristic music of the time. Plagal songs in a major key with perceptive functional chords behind their melodies also entered Hungarian tradition at this time. Plagal tunes, unfamiliar to Hungarian folk music, were sometimes transformed into descending tunes. The antecedents of the new Hungarian folk song style hardly feature in these sources — this style probably developed in the late 19th century. However, among the popular art songs that flourished from the 1830s onwards we found about a dozen melody types with a partial or full similarity to 18th-century melodies.