Abstract: A method of thematically classifying documents, in particular for making up or updating thematic databases (42) for a search engine, includes the steps of selecting documents representative of each theme, identifying within the selected documents, elements that are characteristic of each theme, allocating a coefficient (R) to each identified element, said coefficient being representative of the relevance of said element relative to the corresponding theme, and for each document (50) for classification, identifying said elements characteristic of each theme contained in the document and, for each theme corresponding thereto, using the coefficients allocated to said elements to calculate the value of a characteristic representative of the relevance of the theme for the document (50), in order to decide whether or not the document relates to the theme.