The computation of Feynman integrals often involves square roots. One way to obtain a solution in terms of multiple polylogarithms is to rationalize these square roots by a suitable variable change. We present a program that can be used to find such transformations. After an introduction to the theoretical background, we explain in detail how to use the program in practice. Program summary Program title: RationalizeRoots Program files doi: http://dx.doi.org/10.17632/gbcc9z9tdb.1 Licensing provisions: GNU General Public License 3 Programming language: Mathematica, Maple Nature of problem: Analytic solutions for Feynman integrals are critical for accurate theoretical predictions in high energy particle physics. The computation of these integrals often involves square roots that need to be rationalized via suitable variable transformations. Solution method: Appropriate variable changes for given square roots are constructed by parametrizing algebraic hypersurfaces associated to these square roots by families of lines. (C) 2020 Elsevier B.V. All rights reserved.