Abstract This paper treats the use of third-person pronominal objects le , lo and la in Amazonian Colombian Spanish. Pronoun selection was analyzed in relation to linguistic variables (case and grammatical gender of the co-referent), extra-linguistic variables concerning the speakers (age, gender and occupation) and a geographic variable (municipality). Results show that only linguistic variables have a significant effect on pronoun selection. In particular, we observe a significant interaction of case with grammatical gender, indicating a greater proportion of leísmo for feminine co-referents than for masculine co-referents. These findings contribute to understanding Spanish third-person pronominal objects in language contact, with additional insights about competition and second language learning strategies.