In this study, the novel named Noce i Dnie (Nights and Days) which was written by Maria Dąbrowska, who have made a distinguished name for herself with her prose during the interwar period of Polish Literature, will be reviewed in the contex of roman-fleuve genre. The novel introduces the change and development of a family through the four generations of Niechcic family while reflecting historical, social, economic, politic and culturel changes occured during these years in Poland. In accordance with the river novel genre, it has the characteristics of historical novel, family novel, period novel and autobiographical novel. Events that are told with a quite detailed style, go back to Congress Poland with flashbacks and continue to the World War I. In this regard, many characters and cities are included in this work. Nights and Days, which was published in four volumes, is one of the most important examples of roman-fleuve genre in Polish literature.