This dissertation is a comparative study of three novels: Nana (1880) by Emile Zola, La desheredada (1881) by Benito Pérez Galdós and Santa (1903) by Federico Gamboa. The three novels deal with the life of a young prostitute, one in Paris, France, one in Madrid, Spain and one in Mexico City, Mexico. All three have been traditionally classified as naturalistic, and while they have more than just the theme of prostitution in common, they deal with naturalism differently. We establish the points of contact between the novels to be able to compare them in the context of naturalism. In doing this we will determine to what extent Galdós and Gamboa adhered to Zola's model of naturalism and we will establish the main differences in the use of this model. At the same time we will bring to light the presence of certain topics such as narcissism that are not traditionally studied in the context of naturalism in hopes to expand the scope in this field of study. With this project we open the conversation on the magnitude of Zola's influence in literature, especially in the Spanish-speaking world. At the same time we highlight the idiosyncrasies of the other two authors in writing what would appeal to their audience. We will show how naturalism is not a set of rules to follow, but a set of guidelines that correspond with the trends of artistic expression and thought at the end of the XIX century.