In this paper, we study the extraction of roots as presented by Al-Kashi in his 1427 book “Key to Arithmetic” and Stevin in his 1585 book “Arithmetic”. In analyzing their methods, we note that Stevin’s technique contains some flaws that we amend to present a coherent algorithm. We then show that the underlying algorithm for the methods of both Al-Kashi and Stevin is the same.