This paper examines the consequences that the element of deceit has in the establishment of misrepresentation in a tort. It focuses on the effects that fraud (or deceit) as an element of misrepresentation or as an autonomous vitiating factor in Chilean Contract Law can have in the invalidity of a contract. More precisely, the paper focuses on the relations between fraud, misrepresentation and whether the contract might be voidable or void ab initio, showing the different positions for the lawyer to argue and the Judge’s position when confronted with said questions.La presente investigación tiene por objeto explicar las consecuencias de la instrumentalización que el dolo hace del error esencial, especialmente la concurrencia de las acciones de nulidad absoluta y relativa frente a la existencia del dolo y el error esencial en el acto jurídico, señalando las opciones del litigante y la posición del juez frente a la situación descrita.