All nouns in Spanish have grammatical gender, with obligatory gender marking on preceding articles (e.g., la and el, the feminine and masculine forms of "the," respectively). Adult native speakers of languages with grammatical gender exploit this cue in on-line sentence interpretation. In a study investigating the early development of this ability, Spanish-learning children (34-42 months) were tested in an eye-tracking procedure. Presented with pairs of pictures with names of either the same grammatical gender (la pelota, "ball [feminine]"; la galleta, "cookie [feminine]") or different grammatical gender (la pelota; el zapato, "shoe [masculine]"), they heard sentences referring to one picture (Encuentra la pelota, "Find the ball"). The children were faster to orient to the referent on different-gender trials, when the article was potentially informative, than on same-gender trials, when it was not, and this ability was correlated with productive measures of lexical and grammatical competence. Spanish-learning children who can speak only 500 words already use gender-marked articles in establishing reference, a processing advantage characteristic of native Spanish-speaking adults.