This thesis explores the works of the Colombian writer Fernando Vallejo in terms of autobiography and fiction. Using the theoretical approaches of Philippe Lejeune in his book On Autobiography and Serge Doubrovsky in his book Fils: Roman this thesis will draw distinctions between autobiography and what Doubrovsky calls "autofiction" in Vallejo'­s collection of five texts known as El rio del tiempo. Lejeune has shown that the canonical form of autobiography is characterized by the equation author=narrator=character. However, if we apply this clear-cut definition to Vallejo's book, a series of question arise: Who is speaking in his novels? Can we unequivocally attribute the narrator's ideas to Vallejo himself? Or if his novels are mere autobiographies, why does Vallejo use some blatantly fictitious situations? Fernando Vallejo'­s work underscores the fine boundary between fiction and autobiography and the impact that this relation has on his readers. In his writing, the present time and past time are fused in the capricious channel of his memory, confirming that every autobiography, no matter how sincere it is, is also a form of storytelling.