This paper presents a sociolinguistic analysis of the cases of absence of a preposition before the relative que recorded in a corpus of spoken Spanish from Santa Cruz de Tenerife. This construction is censored by prescriptive grammar since it is considered that the relative undergoes a grammaticalization process; that is, it loses its pronominal character to become a conjunction. The results of the analysis, however, show that both this and the equivalent construction with preposition are mere sociocultural or stylistic variants of a same syntactico-semantic structure.