This article is an attempt to answer the question whether Descartes had read Sextus Empiricus’s Outlines of Pyrrhonism. At first glance, the question seems trivial. This question, however, is of historico-philosophical significance in that it reveals, even if only partially, what Descartes, who is regarded as the father of early modern philosophy, inherited from his earlier intellectual legacy in formulating his own philosophy. I first compare statements from Sextus’s Outlines with corresponding statements from Descartes’s writings to identify their similarities in (...) terms of content. This comparison focuses on their views regarding four subjects: the syllogistic, moral guidelines, the use of definitions, and true opinions. I then analyse and discuss whether the degree of similarity between these sets of statements is sufficient to conclude that the particular work of Descartes is based on Sextus’s arguments. This preliminary study can only provide indirect evidence that Descartes had read Sextus, for a thorough clarification of whether he read anything other than the works he himself stated that he had read (e.g., Cicero, Suárez), would require further circumstantial evidence, however weak it may be. (shrink)