This article highlights elements of Peirce's philosophy used in recent psychoanalytic literature, showing how contributions from Peirce's ideas could clarify psychoanalytic matters. The subject of one of the papers is how Peirce's semiotic could help to fulfill a conceptual gap in psychoanalysis in relation to phenomena that occur between what are called “symbolic equations” (representations lived as facts, by psychotic patients) and symbolization (in psychoanalytic terms). Another article questions Lacan's conception that the unconscious is structured like a language, suggesting that Peirce's signs, particularly the icons and indices, would be more appropriate to think about the unconscious than the linguistics used by Lacan. The third paper gives a good example of how Peirce's philosophic notions can be enlightening in the clinical area, as they are used to answer the criticism that words could not be understood by a baby in a “mother-infant” treatment. The last paper has more complex issues, as it attributes meanings to some of Peirce's conceptions that need to be discussed. In a final part the Author refers to publications in which he examines relations between Peirce's philosophy and psychoanalysis, mainly with Winnicott and Bion's ideas.