The purpose of this paper is to identify Spanish elements in the sonatas of Domenico Scarlatti and to determine the extent of their use. All 555 sonatas in facsimile edition, edited by Ralph Kirkpatrick, were compared to the printed anthologies of Spanish folk music by Kurt Schindler and Felipe Pedrell as well as recordings of authentic Spanish folk music. The study concludes that Scarlatti incorporated Spanish musical elements extensively. In some sonatas, fragments of folk tunes occur, but always with some rhythmical alterations or melodic elaborations. Only K. 513 contains an entire folk tune. Scarlatti evidently wrote melodies of folk-like quality and did not merely copy the folk tunes.